In each case, either:
The sole, shining, exception to this is the britishairways.com site. It's up, it's quick, it works, you can choose your flight ...
They don't take switch cards.
Stuff it. I'm going to swim there.
No, I'll turn up at the LHR BA booking desk with a wad of cash. That won't excite any suspicion at all.
Perhaps I'll try again later tonight.