Very true, I'm half expecting Matt Lucas to show up in a future episode after his brief cameo in Casanova.

In fact, a Mark Heap/Kevin Eldon double act would be just too good.

I think that would win the title of best Doctor Who episode/story ever. Apart from Caves of Androzani, of course, which is just THE BEST, no matter what the experts say when they only ever award it third or fifth place in polls...