The Triton Range of electric Showers are excellent . The T80XR is also. Triton give a 2 year guarantee with there units unlike other makes who give 1 year & you pay too much. Triton also will send out an engineer to repair you unit within the Guarantee time.
As for the heat problem & the fault it all depends on the quality of your water, does your kettle have heavy scale or light chalky scale or none at all( That is without treated water ). Water plays a big part with shower heaters they are only small. So before you condem a unit look at why it failed. Yes your heater element may have failed & yes may as well renew the whole shower, unless it is under Guarantee. Yes it could be the Stat or no water could be faulty Solonoid valve. Generally its the Heater unit, they do a lot of work & if you count the amount of times they are used per day in a family of 4 household , 2 years 9 months later ( say once a day 4 times = 4,015 times ).
I would still recommend you buy another Triton but get a higher KW output rating 10.5 or above. then you can keep the pressure up and turn the dial down. But note Higher Kw output means higher rated cable to your shower & a RCD to your Consumer( Fuse) box.
Contact a good electrician with all the Qualifications to do work in a Domestic situation. & Plumber
Mr J Hargreaves, April 2010