I topped it up with oil and it seems to be holding it so prehaps its not oil contamination. It got me home, just about, took the motorway so that I could stick it in 5th and just cruise and was fine. Until we got back to Bristol that is, where it was juddering and squeeling.
Anyway I had to pick a parcel up from the post office so nipped down there this morning which is only a mile away. Got there alright was playing up when parking. On my way back though got out the carpark and got loads of squeeling and smoke from under the bonnet. So called the AA who have just dropped me home, guy seemed to think it was the release bearing, although cant see how that would fail on a 2 month old clutch?! The guy did ask, "is that the honda engine" so knows his knowledge of MG and the KV6.
The car is currently sat on my drive feeling sorry for itself.