You did it! We figured this one out! It is a truth universally acknowledged (by me for certain) that the Bitchery pretty much knows everything, and really, it's true. Scroll down to see the solution for this HaBO - and many thanks!

This HaBO comes from BellaInAus, who is looking for a book by Reader’s Digest Condensed Books:
My grandmother used to buy the Reader’s Digest Condensed Books, and although I didn’t read many of them, there were a few that stuck in my head. One of them is this book, which has driven me nuts ever since because I cannot remember the title, the author or the name of the heroine and I don’t have the Google-fu skilz to find them. I think this was a fairly new RDCB when I read it, but it would have been in the late 80s.
The book was a Victorian historical and begins in India, where Our Heroine is a child living with her parents. Daddy is an officer in the British Army. The local rajah/sultan/warlord raises a rebellion, and the army post are all killed. Our Heroine and her mother are taken captive and put into the rajah/sultan/warlord’s harem, where they do haremy things. Mummy dies, and Our Heroine is fully inducted into the harem, as it were. I seem to remember that she was a favourite because she had red hair. (Of course she did, this was the 80s.) Anyway, also in the harem is a Greek doctor. After Our Heroine is grown up the doctor escapes, or is released or gets out somehow and makes his way to the British Army and lets them know that there’s a British girl held in the harem and they can’t have that now, so they attack the rajah/sultan/warlord and rescue the girl. She is identified and returned home to England.
Safe in the arms of her loving family, Our Heroine discovers that life as an upper class English maiden insn’t all it’s cracked up to be. Her family aren’t completely convinced she’s not an imposter and are Righteously Mortified by her constant blunders in the secret unspoken ways of a proper English maiden. There’s condemnation because she isn’t a virgin (she has a realistic attitude about this – how could she manage to be a virgin in a harem, and it wasn’t her fault that she was there in the first place). The incident that stood out to me was that they took her to church and during the hymn singing there was a line which all the women didn’t sing. Except Our Heroine, who didn’t know and she was enjoying the singing so she sang loudly and everyone in the church knew it was her. When she got home she was scolded for singing about “lower limbs”. Ladies don’t mention lower limbs. Oh, the shame of it all. Ahem. Her worst critic is her grandmother (or perhaps a much older spinster aunt) who is very bitter and angry about the whole situation and expects Our Heroine to conform to all the secret rules without being taught any of them.
Eventually, Our Heroine leaves the loving bosom of her family and goes on a holiday to the seaside. There, she meets an odd but charming man who runs ‘Lord Boot’s Punch and Judy Show’. There’s detail about how a Punch and Judy show works. Lord Boot is a gentleman, but doesn’t really care about What Society Thinks, which is an attitude that Our Heroine finds refreshing and attractive. Our Heroine meets Lord Boot’s mother, who is nice and motherly to Our Heroine and encourages her to spend time with Lord Boot. I think that the mother says that Lord Boot never really fitted in. At some point, Our Heroine makes a bit of a joke about the guy being ‘Lord Boot’, which sounds like a made-up name to her and she is embarrassed when he tells her that Lord Boot is actually his real name. (I would have totally done the same thing.)
Eventually, Our Heroine and Lord Boot decide to get married. She goes back to the ever loving bosom of her family and gets a visit from the Greek doctor (remember him?). He confirms that she really is who she says she is, and he turns out to be the long lost unsuitable because he’s foreign love of the cranky grandmother (or aunt).
I have no idea if there was sexytimes or not. Now that I’ve rewritten basically the whole story, is there anyone who can tell me what the title is?
This was a wild ride from start to finish.

Don’t know the book, but Wikipedia has the entire list of RDCB listed by year and volume. Just going by titles, there’s several by Rosalind Laker that might fit.
We had probably 10-15 years worth of RDCB’s when I was a kid. Scrolling through that list is like a walk down memory lane. All those books that were popular at the time, but now can’t even be found in USB’s. And a few enduring and important authors.
Is there any possibility that you’re combining a couple of different books? I found this 1985 book which has some weird parallels but is also somewhat different from what you describe: https://www.kirkusreviews.com/book-reviews/madeleine-brent-5/stormswift/
Oooh, I know this one! There are actually two books here but they are both by Madeline Brent (pen name of Peter O’Donnell who wrote the Modesty Blaise books) and both are well worth reading.
The one with the harem and Lord Henry Boot’s Punch and Judy Show is Stormswift and this takes place partly on the Afghan border and partly in the UK. On being rescued from the harem, our heroine returns home only to find an imposter in her place but everyone thinks she’s the imposter. With nowhere to go, she comes upon Lord Henry Boot’s Punch and Judy show, saves Lord Henry from choking on his swazzle (the thing that makes the Punch noise) and joins the travelling show. Eventually she goes back to Afghanistan to rescue the old Greek army doctor who is the only one who can prove who she is.
The one with the loud singing is Mookraker’s Bride where our heroine grew up in a Chinese orphanage, was rescued from prison by marrying a man who was about to be executed there and is then adopted by a wealthy family who are very disapproving. There’s a feud with a nearby family, she’s very nearly killed and rescued by a mysterious stranger and then her dead husband comes back to life.Oh, and she has to return to China, in the middle of the Boxer rebellion to save the orphanage and find a mysterious treasure.
I love Madeline Brent’s books, they are fantastic eighties gothics with evil relatives, spies, treasure hunts, handsome men who might be killers and all sorts of shenanigans and some really unconventional heroines. I think they’ve been out of print for a bit though but you might be able to get some second-hand.
Some parts of this sound like “Moonraker’s Bride” by Madeleine Brent, and some sound like “Stormswift”, also by Madeleine Brent. Moonraker’s Bride had the hymn singing episode, and Stormswift had the escape from the harem and puppet show episodes.
What Elizabeth said. I think both were Reader’s Digest Condensed Books.
Well, late to the party again. Yes to Em, Elizabeth and LauraL–y’all beat me with the answer. I just love, love all the Madeleine Brent books, especially Moonraker’s Bride and Merlin’s Keep. Off to track down a copy of Stormswift for a re-read.
From what I can tell, these haven’t been digitized at all.
Moonraker’s Bride on the Open Library (with a long wait list):
https://openlibrary.org/works/OL5091766W/Moonraker's_Bride
Stormswift: https://openlibrary.org/works/OL5091763W/Stormswift
Glad to see several others recognized Madeline Brent! The hymn scene is right out of Moonrakers’s Bride. Our Heroine sings “virgin” loud and clear to the horror of her snobby guardians. I’d go on but I’m at work. Time to reread all my Madeline Brent’s.
I too recognized Madeleine Brent immediately. “She” was known for the fish out of water trope, and that the heroine’s knowledge of the other exotic world she came from always saved the day in the end. I am very fortunate to actually have all of “her” books still on my shelves.
Love Madeleine Brent and have been lucky enough to find two titles in thrift stores as well as having a paperback I bought as a teen. I continue to hunt. Wish they would be re-issued or digitized.
You guys are AMAZING.
When I went to bed last night this wasn’t even up yet, and this morning you’ve solved it!
I remember the swazzle now.
My mother was very anti-romance novels (still is, actually) and I could have sworn I only snuck in the reading of one of these. But now I have two to read. Yay.
Assuming I can find them.
Ooh, a Madeline Brent I hadn’t heard of! Must be off to scour bookfinder.com and ebay!
All the Madeleine Brent books were republished in trade paperback a few years ago, most with really good covers. You can find them on Amazon and B&N.
I haven’t read Madeleine Brent before but when I am looking for used books I check thriftbooks.com as well as Amazon. I found both books mentioned, one for under $5 and the other under $9. Have to scroll down and look at all the books listed, will have same book mentioned multiple times. Some of the sellers here are same as sell on Amazon. Good hunting.
This is my favorite Madeleine Brent book!!!! Interesting factoid – Madeleine Brent was the pen name of a British Intelligence Officer who wrote a ton in the 60s and 70s. The book was set in Afghanistan, not India. The heroine was captured during the second Afghan War. I want to say it’s either Stranger at Wildlings or Stormchaser. I own both and can check when I get home. I first read these in my library when I was a teenager. I came back to it when I was assigned to Afghanistan.