Low pressure

It may be your solenoid valve, you can check it if you have a multi meter, you should have a reading of at least k3.5 ohms, across the two terminals any less and you need a new valve. (Check the valve in the failed state.) (When it has stopped working!)

If there is power getting to the solenoid and it is not operating then there is a good chance that you have a faulty solenoid.

http://www.youtube.com/watch?v=NzJjzWqxesc

The video is intended as a guide and does not cover every shower.

If you don’t have a multimeter  we sell them  with a guide on how to use them for checking and testing the various parts of your shower.

Apart from helping to fix your shower, they are really useful for checking you have a power supply to appliances, for checking fuses and letting you know much power you have left in batteries

(So you will know if they are good or not) and lots of other jobs, in short they are well worth a few pounds

http://www.showerdoc.com/installation/electrical-products/SKYTRO-600-005-Digital-Multi-Tester

And I think that you may have a leak from the stabilizer valve which has caused the solenoid to become faulty.

If the stab valve is faulty you will need to replace it and the solenoid unfortunately the stab valve is now obsolete so you are looking at a new shower.

This is probably the easiest replacement

http://www.showerdoc.com/showers/triton/electric-showers/ztrito-sp8009zff-triton-t80z-fast-fit-9-5kw-electric-shower---white-chrome