Update:
RESULT!
After spend mucho time on this mini DIY fix it job, I have finally had a result and I'm delighted!
Turns out the one of the springs behind the brush had lost its 'springiness'. As a result the motor was going bad. The gas guy (who is now my friend!) said he'd previously helped a guy with a Q7 who had had a similar problem.
It turns out this guy with the Q7 works in/owns? the garage next door (tyres and exhausts place), and apparently still has all the spare bits lying in a box somewhere. His Q7 had other issues to from what I was told, and I'm not sure he had fixed the issues.. So my new friend suggested that I go around there and ask if this chap still had the spare bits from his motor.
Sure enough, I got the box (just gave it to me), and was about to swap one of the springs over, then decided to just swap the whole side section out (the part of the motor which has the two power cables running into it. Its a little tricky as you have to somehow retract the two brushes and the springs behind them before you can fit it onto the spindel of the commutator.
Finally got the motor working, and managed to get some air pumping. Although I couldn't get a proper reading, I tested it by placing my index finger over the output hole, and it was decent. Andy from bagpipingandy suggested this technique and said not to worry about getting an exact pressure reading.
So.. managed to put the whole thing back together (I had taken pics as I knew I would forget!
)
Mounted it back onto the car, tested it by manually actuating the relay, and hey presto! we had a working compressor!
Switched the engine on for the moment of truth.. nothing.
Remembered car was in jacking mode, switched this off, straight away something, and then all the options become white from being greyed out, and its working again!!!
In summary, Delboy was right on the money when he said:
"The fault codes are quite generic and don't really say much as it could be telling you there's a leak or it may be that the pumps just worn out and the lack of pressure is giving the same error"
I believe that because the motor was on its way out and behaving, at best, intermittently, this was the cause for the errors.
The lights have gone out themselves, and I just need to get VCDS scan again to see if the errors have gone away.
I do feel that the kit from bagpipingandy would make it pump more pressure, but not sure how this would affect the air suspension? would it raise and lower the car any quicker?
Also, I was thinking to wire a buzzer or a light to the relay, in order to monitor how often and for how long the compressor is kicking in; mainly because I want to prevent it from heating up/burning out. That said, both my fuse and relay were fine.
Thanks to all those who read my posts, and especially to Delboy
Hope this has helped someone..
....shopping list now needs a VCDS cable and software adding to it!
