Turns out my ECU is knackered.

My hot start problem, mutated into just a start problem.
Then a, if it starts, it runs on 2 cylinders.

Checked everything and only injectors 4 and 2 fire, 1 and 3 do nothing.

Wiring loom ok, tested with a meter...

injectors ok, swapped them around and fault stayed on 1 and 3.

Only common factor ECU, Plugs and connections are ok. Plugged into computer via OBD, no codes stored...