Hi Geoff,
by reworking the head I meant strip & fit new valve guides /valves etc.....
I've heard of the heads cracking after new guides have been installed & received too many reports off folk who attempt head repairs on the single cam 1.2 suffering misfire faults again.

I recently heard of one via another garage where the head had been sent to an engineers 3 x to resolve misfire issues.

Some of the above is covered in a lengthy dealer bulletin that involves testing everything in a long winded process & ends with, "if all of the above fails, replace the cylinder head"

We cut out the middle man - compression test when misfire is present, if any compressions are 15% off spec we fit a new head.

I can root out the bulletin & email it to you if you like?

The software update is a Dealer tool or Autologic user affair.

A couple of local workshops have fitted new heads & then sent them to us for the update to be installed.

Jon.