would it not be then for your landlord to replace it? they aren't that expensive. This is what I got http://www.gainsboroughshowers.co.uk/shower-store/electric-shower/Gainsborough-105-se/ and about £100 for a plumber to fit it. What I like about it is that the heat settings are gradual rather than the ones which have 3 buttons for cold, mid temp and hot. Temp is controlled on the dial.