Right, we might be getting somewhere, been dow to Warrens place in Sheffield & put the car on Rovacom. It had a fault showing on the heater matrix sensor (as i suspected) along with a few out of calibration errors that he cleared. I am going to replace the clip on heater sensor at the same time as doing the heater O rings. He also drew my attention to a fix for the lazy AC pump clutch, apparently it doesnt get enough voltage so doesnt engage some of the time. There is a repair kit number YMQ104590AA That fixes this with a relay.
You can easily tell if this has been done by looking at the relay box under the bonnet. There will be a realy in the 2nd alaong slot on the bottom row (normally left empty)
This is a more than likely cause of mine, along with the fact i need to take out the shims too.
HTH someone!
Nige