Just read all the posts, and a little thought has occured to me..would this debate be going on if say the new BA business route from LCY was to say DME (Moscow) as a there and back. Rather than a nightstop in New York and poss a night in SNN on the way out.
As for cost etc..LGW crew (if its a night stop SNN first) could actually report at LGW, have a full brief and still position by road to LCY op. to SNN and still be in hours without even triggering overtime.