Hi Del
Thanks again for following the posts and replying.
Deffo good news about the compressor - man that thing was a nightmare to get out! (ended up purchasing some L type keys with Torx ends, a bit like allen keys) - wish I had had these for the job.
Anyway, I was also thinking about getting the bagpipe kit, but didn't know how to check if the piston ring thingy needed replacing? but yes, it certainly makes sense to spend the £20 odd quid since I have it out already.
The guys that did the scan for me printed out the logs for me, so I will see if I can take a snap and upload them. But yes it would hopefully prove worthy to try and diagnose the issue.
I am going to cancel my appointment with the garage tomorrow, and hopefully see if I can resolve myself... of course with the help of fellow forum chums!
I have also found these threads but unfortunately some of them do seem inconclusive.