All fascinating stuff. I remember travelling on a Ford press trip to Jerez in Spain (vehicle testing), and they flew us hacks out in a B737 configured all-business. A bit like BA’s service from LCY to the US, but this was about 12-13 years ago.
We flew out of Luton, IIRC.
The aircraft actually stayed parked at Jerez for the two days we were bashing things around the circuit, because it was cheaper to do that and put the crew up in a hotel than to rotate it back to the UK and out again.
The cabin crew loved it – when we re-embarked, they all greeted us ecstatically, sporting lovely suntans, and wishing aloud they could have more jobs like that one.