Immersion and timers

Is it worth using a timer with an immersion heater? Yes. electricity is very expensive and you don't want to use it unnecessarily.

I have a "one-shot" button on the immersion heater timer. In one-shot mode, it will heat until the tank is hot and then stop until the next timer event. So I can have a bath in the evening without leaving the tank full of re-heated hot water, all night. I have it set to heat another tankfull in the early morning, which does for a shower when I get up and the hot water I need during the day.

Will that kit do the job? It certainly wouldn't with a hopper-fed coal boiler. But i can only guess what system you have.

The best place for thermostats, IMHO, is on every radiator. But, YMMV. hallways seem the traditional place...

It should allow seperate controls of the HW and CH as long as you can do the plumbing and electrics. It is the equivalent of the Y plan shown here

Use a TRV on all the rads, except the rad in the room with the wall stat. This room should have no secondary heating (ie not in a lounge with a gas/electric fire or in a kitchen with it's cooker)

The usual place is the hallway

Adam