Hello Phil, I've been working hard to find a Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.
I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.
The engine light is not on when running. As regards the diagnostic codes I am afraid I don't know these as my mechanic did this work (normally very good) , just disappointed he ended up replacing all plugs and coils ...and still just the same :-(..