I have a friend flying LHR-MAN, and 5 hours later I am flying LHR-LIS on TP. I'd like to guest them into the GBL/Heathrow No.1.

Has anyone any experience of turning up to the lounge quite a long way before departure? I know *A rules say "boarding pass for a same day flight", but has anyone stretched that out 6 hours?

(I've spent 6 hours in a lounge before, but only as part of an obviously mis-connected itinerary!)