Can anyone recommend an electric shower, exsisting shower seems to have a broken thermostat as only geting cold water.
It could be that the heater can has simply failed. Or the thermal cut-out - have you checked that?
But having a thermostat is a good point - most electric showers just have a crude anti-scald system, so when someone turns on a tap or flushes the loo the shower goes very hot, and won't cut off much before it gets to the point where it'll actually injure you.
Some have proper thermostatic controls.
[code:1] I have a combi boiler, but as electric showers use the cold water feed does this even make a difference? [/code:1]
No - you can't supply an electric shower from a combi.
You might be able to supply a mixer one though.
Preferably easy for DIY'ers to install using exsisting plumbing/wiring.
Give thanks to the DIY gods if you manage to find a shower with the water and electrical inlets in the same places as the current one.
Current shower is a Aqualisa Quartz electric 8.5
8.5kW isn't very powerful.
What rating is the fuse/MCB, and what size is the cable, how long is it, and dose it go through any insulation?
Does the circuit have an RCD?