but I doubt very much a UK operator would launch across unsuitable airfields
Are you sure of that?
I ask because a couple of weeks back I operated to FNC. T16 heavily in use by all UK charter operators southbound that day due to the winds. T16 REQUIRES LEST as an ADEQUATE airfield (at the furthest point out on T16 ONLY LEST is within 400nm). LEST weather had been forecast, and was, below operating minima (200-300m, sky obs). Under ETOPS rules LEST could never have been considered (as not suitable), but because flights were non-ETOPS the rules say it 'doesn't matter'.
A range of operators, including my own, all operated happily down T16 that day, and legally so. I appreciate the scenario I describe is 'slightly' different, but how different to the one under discussion? If its legal........
We're coming from the same side as to sensibility, but the rules are written as they are, and the above shows that operators WILL operate to what's legal. They put themselves at commercial disadvantage to build in extra 'above the legal' constraints if their competitors don't do so.
30W