Spent time today removing a WC pan, or rather the cistern. The pan
itself is sitting on the floor, loose, waiting to be removed, but I'm
not sure what else I need.

The pan is not being replaced, so I need to block off the exit/waste
pipe. I thought I needed some sort of inflatable balloon that goes in
the waste pipe. Is that right, and if so, what is it called? Searches
involving pipe and balloon just bring up plastic things to stop leaves
going into waste pipes from gutters. Perhaps I just need a 'soil pipe
socket plug'? Or what looks like a ribbed rubber plug?

Thanks!

--
Graeme