Right, had a spare moment to peruse the wiring diagrams!

It would seem (and from logical reasoning) that short or issue I am having is possibly related to the purge canister wiring which is also connected to Pin 20 (ecu power +ve).
According to the diagram it looks like the positive from the battery splits and goes into two, one for the fuel pump relay (M10) and the other for the fuel injection relay (M11), they each have their own fuse and only one of them blows.
From logical reasoning it seems the the fault would be AFTER the relay given than there is no issue with the car when ignition is off and therefore the relay is not operating and completing the circuit, as soon as you turn the key the relay operates and the fuse blows.

On the diagram the purge canister is bridged into pin 20, I have not checked the location of this part but I beieve it is somewhere near the turbo on the drivers side of the engine bay.

As always thoughts and inputs appreciated.