On Sat, 19 Sep 2015 16:54:42 +0100, Chris French wrote:

Someone on the local Freecycle was offering a load of darkroom gear,
which I've acquired. And I've rooted out my old film SLR. So now need to
construct some sort of darkroom space.

The problem with a cellar is drainage. Prints need to be fixed, then
(ideally) washed for a LONG time under running water. Unless you can get
a decent sized bath tub in there to collect the run-off, using the cellar
could be problematical.