I agree with merrymouse and Yuddiesorno. I’m an ex Londoner, and live in Yorkshire. It isn’t exactly a cultural desert here you know.
Also exams may not even happen this year so restarting GCSEs without the current pressure she faces sounds like a bonus
I doubt that many state schools will allow 15 year olds to restart year 10s. A private school may well do.
I suspect some posters may be a bit distant from the GCSE experience. and even then, they only had knowledge of their own GCSEs
I agree with this ^^
I'm not being funny but GCSEs aren't the most important thing in the world anyway.
I’m sorry, but for today’s 16 year olds they are more important than ever @LucyLockdown 
Regardless of what happened 20 or 30 years ago, or even 10 years ago, not having at least English and maths GCSEs will severely restrict job opportunities. Why would you do that to a child?
Also Devon is rubbish for teens, there's nothing to do and not many work prospects
What, in the entire county of Devon? Not even in the larger towns and cities – Exeter? Plymouth? Other towns?
I wouldn’t do it until 6th form
I think that would be the worst time. I made great friends in secondary who remained friends in 6th form & still are to this day. I think making new friends in 6th form would be really hard.
IME if she went to a 6th form college rather than the 6th form of a school then everyone wants to make new friends, and settling in would be much easier.
I did year 10 and 11 in one year so I didn’t have to be held back a year.
The GCSE syllabus has changed in recent years and has a lot more content than when you took them. Also, the OP's DD wouldn't thrive under that kind of pressure.