Got my car back yesterday, and it seems that they have finally sorted my power loss problem.
Turns out that a wire from the TDC sensor to the injection computer had been rubbing on the gearbox, and shorting the signal to ground every now and again!!!
Will find out once i get on a long run, but fingers crossed.
Oh, reno tech solution 2409 - Poss cause Rodent damage, result from my car - no rodents found!!
sh*t you not thats what they tried, i got a copy of all the reports