Heathrow

I am flying from Terminal 3 later this year to Cape Town with BA. Unfortunately, this flight goes from Terminal 3 and I love Gordon Ramsey's Plane Food restaurant in Terminal 5. Is there anyway I could go through security at Terminal 5 and then transfer to Terminal 3?

You won’t be allowed to go airside in T5 with a boarding pass for a flight from T3.

However if you’re that eager to sample Mr Ramsay’s finest, you could always buy a fully flexible ticket for a flight that leaves from T5 at around the same time, use it to get airside, cancel it for a full refund, eat, then jump on the transit to the C gates but stay on board and return to the main terminal as an arriving passenger, then follow flight connections to T3 using your real boarding card.

A little unconventional admittedly ...