Update in case anyone else is trying to diagnose the same problem...
If you haven't already done so it may be worth checking the engine coolant temp sensor. If faulty the ECU may be misfueling.
Using Engine Check I could live scan the temperature sensor and it's giving logical readings from ambient all the way up to running temperature. Scanning the
pressure and timing advance simultaneously shows everything looking logical with the car stationary.
As soon as the engine is put under load - "bang", rough running, no response to throttle, advance jumps to 30 degrees, electrical fault warning light on. No DTC's stored, no MIL light.
Next checks: injector operation and get the
tested, ask elsewhere on the forum if CAN CLIP will give information about what switches the Electrical Fault Light on. I've even sent a message to a contact in Germany to see if I can get a flow diagram of how the