Alan - Many thanks for that. Hope all is well with you.
Steve - the vacs (sometimes one, sometimes both) are cutting out. When I say that, I don't mean stopping, what I mean is that the motors are still going but all suction suddenly disappears. I think this is meant to be what happens when the waste tank fills to the top but it's happening when it's empty. There was also a distinct smell of burning vacuum motor at times and at one pont some water came out from under the bottom of the machine, accompanied by what looked like some steam.
It's the 1003 dx, the green one as supplied by cleansmart in 2006/7
Cheers
Owen