UPDATE: Although I have not got my car back yet Ross at RBM has removed and refitted my EPS motor/ecu and confirmed it is working again after being sent to ECU testing for repair.
Ross also had another Z in with the same problem and ECU testing's repair again fixed that.
Got my 2.2 Z back from Ross and the steering is fine now. He is a valuable man to know and does exactly what he says.
He is an hour away and I drove the Z without power steering up to his place in Hook and 2 weeks later I get the Z back and he even put the clock right too
For future reference there's a garage in whitstable that are or certainly used to be bmw specialists called Unit 5. Don't know if they are any good or not, the others I've heard of in kent are h and c in maidstone and ETA near brands hatch.