Further info, taking it easy plus waiting in traffic for approx 10/15 mins over half a mile, it started again on tickover this time. Car was shaking, got cd up and couldnt turn it down quick enough to listen. Gut feeling its when its warm/hot before fan kicks in, still normal temp though.
Luckilly i was on me way to fetch some drop links from an independant VX specialist £11.5 each genuine, so had some plugs as well. This dealer rang someone up in Liverpool an ex VX service bloke, he was stumped but mentioned MAF sensor and knock sensor. notsure.gif
I mentioned EGR valve had seized but was blanked off and ran a lot better, contrary to advice by a local VX man.
Initial symptoms felt like valve burnout without trying to keep the engine going dunno.. Had this on a Cologne V6 turboed.
Will try and narrow the problem down some more electrical or mechanical, unless anyone else has had a similar problem they can share.