Power Delay Relay M5
 

What does this do and do I need it?

Provides powerup controled by the ECU ( no idea why ), provides a switched supply to the pump relay (Which I think we have covered off already).

TT

Well it looks like it's got a black wire going to a solder joint where loads of other blacks meet, another black going to the edis, a brown going to a common earth point, and a red that goes off and splits to then go onto the ecu and engine management relay. I think it's the engine management relay you're thinking of for the switched feed for the fuel pump.