The Watermill Theatre responds, rather swiftly. They're not looking for scripts at the moment.
Which leaves me with the Questors sub, at least until I submit some more.
Between the two, I would have said that Watermill was more likely to succeed. After all, there's all that history with Questors, trying to get there and everything.
Mind you, about a few months on giving up Uni at Ealing I was back there, so you never can tell...