It's furnished already, which means I'll have to find something clever to do with a few of my own bits of furniture, but on the other hand I'll be more than happy to lose my slightly-foxed-and-extremely-catted sofa,

Can I be rather opportunistic here, and suggest that it's got to be better than our vague approximation of a sofa, and could probably find a happy home at Alpha Road.

Fraying, which you say your sofa has, can always be disguised by a throw, unlike a bad attitude and a tendency to tip people onto the floor, which the sofa at alpha road has :)

I'll bear that possibility in mind, but I'm afraid Relativity has also put in a bid since they'll lose their current sofa when mobbsy takes it with him to the flat he's currently buying. Since they then won't have a sofa at all, I think their need is probably greater than yours. Sorry :-/ I'll let you know if they turn out not to want it or anything.