It sat for the full year of 2008 and start of 2009 up until about march 09 thats when it had an mot put onto it since then its never been sitting for more than a week.

And how much would that ultransonic cleaning cost? sounds like agood idea.

Finally found the results -

CO - Max 0.30% - Reading 1.04% - Failed
HC - Max 200ppm - Reading 409 PPm - Failed

It passed on the engine speed and the Lambda.

The car has also got 195963

Hope this can help.