Sorry to bump this old thread, but I thought that I'd let you all know how I got on ... in the end I ought a Pro Combi Q 1600, refurbished, from Sterling on Ebay. All went well until the thing just stopped after 5 months - I contacted Charles, as I couldn't remember whether there was a 3 or 6 month warranty - his response? "No problem, get it back here and I'll take a look at it." As a postscript - when I took the unit out, same water ran out of the box - there had been a small leak directly above it, and once it was dried out the unit returned to perfect working order, so there was no need to return it. So, from my point of view, Sterling were very helpful, and the unit is amazing - although I wouldn't necessarily recommend immersing one...
P.S. I did fix the leak though...