See above,,,,,,,,,,,,,,,,,,,
if you want to get the ceramic discs you will need to visit a decent plumbers shop
and details of the mixer will be essential
then you will have to fit them and hope it is them
i would personally get a new mixer
b and q best bet
has the water stopped yet?
can you turn off the hot water by your programmer ?
have you located your main stopcock
should be on ground floor somewhere
outside in the drive or on the pavement there should be a waterboard stopcock
this might give an indication of where your stopcock is (should be roughly in line)
another way might be to follow any earthing wires from your fuseboard one should go to the stopcock
if it doesnt stop i will bring me car round for a mr e special :D