Hi

I think only one gate at t5a can handle dub arriving flights ( a23 unless parked off stand)as you go through a special corridor by passing the walk to flight connections and the uk border. There would be staff at the door to direct you if you had a international flight connection. If you arrive at the next gate a22 then the internal corridor door is not set up to allow this.

You could ask for compensation for the luggage delay but probably unlikely to be given


Regards
tbs