The shower on the first floor is leaking slightly, causing water to drip into the kitchen below, through a crack in the plaster.
I'm wondering what the likely cause of the leak is; I assume it is somewhere in the drainage from the shower, since the shower itself has a single base (plastic or ceramic) which does not seem to be damaged in any way.
I've asked the plumber who installed the shower to have a look, but I'm wondering meanwhile (he is on holiday) if it is likely that I can solve the problem in some simple way.