On 26/09/2011 07:54, Lobster wrote:

Can't see why there would be a problem with changing the taps to one
with a built-in mixer valve:

Nor can I, tbh, I suspect she's got hold of the wrong end of a stick
which has the landlord on the other end loudly saying, "I'm not paying
for it"...

My concern (which extends to your original plan too) would be that the
walls/bath etc are not properly sealed and set up for a shower, and that
there would be leakage - S-I-L would undeniably be responsible for the
damage.

Good point, though the walls are tiled and the bath appears to be sealed
to them, so unless there have been problems in the past it seems strange
not to have provided a shower.

Lee