Might be a scam , perhaps a phone call to the US embassy in London might clarify matters ?
easier said than done I know .
Interestingly you mentioned a tight transit time,
it is more than likely that considerably more time than usual might be spent in transit, Covid checks etc. BA will most likely not have considered this .
Such a pity these days that we all have to be cynically Scam aware and expect indifferent customer service as a matter of course, only to be delighted when confronted with what would be considered thoughtful and efficient customer care. Good luck !