Originally Posted by
Enigma368
Got it thanks! Thanks for the helpful answers. And if, in that worst case situation, they refuse entry at T3 security, do I have to clear border control at T3 and travel landside to T5, or can I just go back to T5 via airside bus?
You won’t be refused entry to T3 - plenty of legitimately connecting passengers may not have a boarding pass and would need to pick it up at a desk after Flight Connections security. You can always say you are using a lounge there if questioned.
You can just get the bus back to T5 if you aren’t let in (not that that will happen).