Stupid stupid stupid me... Filled it up with premium "higher octane" petrol and now it's running like a bag of spanners.

I know they are lumpy at 30 ish, but it's lumpy all the way through now...

****** it, need to start getting rid of the fuel ASAP.

On a good note, it's now doing 57.5 mpg and that's with motorway daily use and TKC80's on. Love it!