Have pulled the connection to each injector and this seems to make things worse (which I take as good, injectors are working, wiring is working). Have pulled the Coolant Temperature Sensor (CTS) which triggers the MIL but makes not difference. I've measures across the CTS and got 280Ohms which based on the table below suggests a good reading.
I've just repaired/replaced the ignition harness (ECU to Amp to Ignition Coil) so I guess it could be this, but having checked it electrically the wiring is sound, resistances low and good supply to the coil etc I noticed there is a small crack in the potting on the top of the coil (Ducellier), but going by the dirt that's in it, its been that way for a long long time.
So, suggestions?
![Image](http://www.bxproject.co.uk/gallery2/var/albums/mods/wiring/BX16vCTS.jpg?m=1391540679)