Hello,

I found old 3-door Cosworth wiring diagram and there M11 receives +12VDC directly from ignition switch. In 3-Door version this wire color is black, but I assume that same wire with your car is black/yellow.
You can try first connect directly +12VDC to M11 relay (Fuel injection relay) terminal 86. M10 relay (Fuel pump) receives +12VDC, when you have +12VDC at M11 relay terminal 86.
So you are looking M11 relay terminals 30 and 86.
-terminal 30 +12VDC from battery, trough fuse
-terminal 86 +12VDC from ignition switch

If these does`t help, ECU terminal 10 is grounding M11 relay terminal 85. When M11 relay works, you have +12VDC at terminal 87.

I`m not however sure is wiring matching with your car, because, as I said this wiring was for 3-door version.

Black/blue wire in ignition switch is for starter motor. This wire goes somehow trough original alarm system.

Ignition SW:

Red/black, from battery
Black/yellow, Cooling fan temp switch and others... (so many places, so not listed...)
Black/blue, Anti theft relay/starter motor
Yellow, ?

Hope this solves your issue.