Originally Posted by
flying.scotsman1
CAA have said it must be an approved school in UK airspace.
UK ORA.ATO.150 says that for an ATO approved to provide training for the instrument rating in third countries (i.e. outside of the UK), the training programme shall include acclimatisation flying and the skill test to be taken in the UK.
There are quite a few ATO's offering both modular and integrated training under a UK approval outside of the UK where students return to the UK to complete the IR acclimatisation and test, some of which have been mentioned. Standards Doc 31 only lists UK site addresses though so a bit of research will be necessary.