My parents live in an old terraced property and have an electric only immersion heater with cold tank above it, they used to get a good flow and a full bath of hot water but they are no longer getting a good flow it takes about 30mins to fill 1/3 of the bath and then the hot water just stops dead.
As far as I am aware the only thing they have had done to the water is the installation of a electric shower.
Can anyone offer some pointers on this issue?