I have a Mira Vision, pumped shower that occasionally, runs cold / won't get up to temperature. Set on 42degs, it is only just body temperature. Last year (I think) I replaced the pump assembly as that was making odd noises. What is the part that I need to replace this time? Obviously some sort of thermostat but is it a large, mechanical item or a small, electronic item? I've attached a pic if that's any help. Thanks
