I've just had a conversation with a FTO where they would only consider me as a FI on their books if either the majority of my hours, or the FIC have been done locally.
Granted the Principles of Flight and the aircraft are the same here as over the pond, but from my (my head on a block here - limited-) flying experience, surely judgement and knowledge learned from local conditions are a big factor.
If you are to instruct in a "Disturbed Temperate Climate" better that you learnt there than in a "Savanah" climate? (Sorry - Met was a recent subject as you can tell
!!!