Indeed EI-REL is in the Purple livery, EI-REM will be repainted/rolled out in the same paint scheme aswell for the Stobart Air/ Flybe franchise routes. The purple paint scheme looks alot better on the ATR’s than the Q400’s in my opinion.
I’m not spitfire expert but I think it’s to do with keeping it level and trimmed. The aircraft would start to climb if the elevators weren’t a few degrees down.