I just got my MS back from the proofreader. I think she did a fine job, but... she changed all instances of "any more" into "anymore".

My spell check (UK English) tells me it's "any more".

Cambridge Dictionary tells me it's "any more", and adds "Especially in American English, any more, as an adverb, can be written as one word, anymore".
https://dictionary.cambridge.org/grammar/british-grammar/any-more-or-anymore

What to do? Accept or reject those changes?

Dan,

She may be using an American 'Spoil-Chucker'.

But I rather doubt if all your 'any mores' and 'anymores' have the same meaning and context ;-)

https://www.thefreedictionary.com/any+more

Yes, our US friends seem to prefer "anymore". Weirdos.  ;D

I guess it just baffles me that a professional proofreader wouldn't know that "any more" is the preferred spelling in British English. You'd think they should have learned that much. I even explicitly stated that I use British spelling.

And no, they don't all have the same context, but most of them are used adverbially.  :)

Whatever would your proof-reader do with the sentence: "Is there any more tea in that pot?"

To answer your question, I would reject the change.  You have all the authority you need, with your dictionary supporting your instinctive choice.  (Can be written is not the same as Should be written, nor anything like.)  While anymore may be acceptable in some circumstances in some parts of the English-speaking world, any more is acceptable in all circumstances in all parts of the English-speaking world.  You can also point out that a single Americanism in the midst of an English text is going to stand out like a sore thumb.  Or possibly a sorethumb.

'Anymore tea in that pot' would leap off the page and assault your brain.

Gyppo

Quote from: Jo Bannister on November 04, 2021, 08:13:13 PM
Whatever would your proof-reader do with the sentence: "Is there any more tea in that pot?"

Good one! I don't think she'd have changed that, but I could totally see her binning the "any" in this case. She did that with some of my stylistic choices - which I am, of course, going to reject.

Quote from: Jo Bannister on November 04, 2021, 08:13:13 PM
To answer your question, I would reject the change.  You have all the authority you need, with your dictionary supporting your instinctive choice.  (Can be written is not the same as Should be written, nor anything like.)  While anymore may be acceptable in some circumstances in some parts of the English-speaking world, any more is acceptable in all circumstances in all parts of the English-speaking world.

That is, indeed, the answer I was looking for. I was starting to doubt myself because English is not my first language. But I checked and double-checked, and felt utterly confused.

Thank you for restoring my confidence.

Quote from: Jo Bannister on November 04, 2021, 08:13:13 PM
You can also point out that a single Americanism in the midst of an English text is going to stand out like a sore thumb.  Or possibly a sorethumb.

Exactly. And I wouldn't want that to happen. I have some characters speaking with a foreign accent. I even threw in a few Dutch words for flavour. But then we're talking about dialogue (and even there I kept it to a minimum).

Quote from: Gyppo on November 04, 2021, 09:33:54 PM
'Anymore tea in that pot' would leap off the page and assault your brain.

Gyppo

Absolutely!

Every so often (or possibly everysooften) you come across a proof-reader or copy-editor who is a failed writer and thinks that, having been unable to make a success of their own book, they'll appropriate yours.  I got one once - just once, out of 40-something books - and I returned the proofs unmarked, and complained about the degree of inference to both my agent and my publisher. 

The publisher, far from leaping on her high horse, was most apologetic and undertook to edit the text herself.  Every suggestion she made was valid, and I think I accepted all of them.  And there were pages and pages without a mark on them.  If you're a competent writer, that's what a copy-edited text should look like.

Quote from: Jo Bannister on November 06, 2021, 03:03:20 PM
The publisher, far from leaping on her high horse, was most apologetic and undertook to edit the text herself.

That's the proper way to handle a situation like that one.  :)

Quote from: Jo Bannister on November 06, 2021, 03:03:20 PM
And there were pages and pages without a mark on them.  If you're a competent writer, that's what a copy-edited text should look like.

This one came back with 181 revisions, including all these "anymores". I think that's not too bad for a MS with a word count of roughly 132k.

No, that sounds perfectly reasonable.  The best among us can make mistakes; and perhaps more often, fail to make something clear enough.  Or even get repetitive in the attempt to be clear enough.  It sounds as if both you and your proof-reader have done a good job, except for her odd approach to one issue.

I think so. I think I'll tell her politely that any more is perfectly good English, so we don't run into that issue again next time we work together. That should save both of us some time.  :)

Hi, hope you are doing great and your work has been published by now. Maybe she had done it for a reason. Maybe she could not find any other issue but she had to change something so she changed "any more" to "anymore". Just kidding. Hopefully, you asked her why thou. Your decision of being polite was right especially if you are going to work with her in the future.

The words any more and anymore have similar meanings, but they are not interchangeable. It depends on how you're utilizing it whether you make another one or two words. Any more is a phrase that alludes to quantity (Would you want any more tea?).
Here are the 11 best English books for students to read: https://mytutorsource.hk/blog/11-best-english-books-for-students-to-read/. 
Anymore is a time-related adverb (I don't enjoy tea anymore.). In British English, the word is written as any more but in American English, it is written as Anymore. If you are a student from a country where English is not a native language then this may be stunningly for you. If you want to know the difference between British and American English and want to speak fluent English you should read English books as much as possible.