On Thu, 3 Oct 2013 17:33:16 +0100, Sam Plusnet wrote:

I would like to use a Terma thermostatic element like

http://www.amazon.co.uk/dp/B00ABGFEX6

How much!

because it gives more control over my Electricity Bill.

But the better half also wants me to fit a 24 hour timer so it can pre-
heat in the mornings.

But do you want to pre-heat at the same time *every* morning? Get
aroundable with a 7 day timer to some extent. Personally I'd just go
for a suitably sized heater(*) and one of the controllers that give
you a timed on period when you want it. Most give you a selection of
"on" periods, from 30 min to 3 hours witha couple of intermediate
steps. Can't be "accidentally" left on like a time switch put into
manual because you are late up and it's gone off...

(*) Not sure if this is a stand alone towel rail or one also part of
the CH system. The latter probably doesn't need a stat as the heat
losses from a radiator/towel rail sized to heat the room will be huge
compared to the electrical input.

--
Cheers
Dave.