Re: Heating Controls.
That one is used and would more than likely be as old as the Caricature is replacing. Too expensive as well.
Any modern 2-channel time-clock will do the job. What type of heating system is it? `S` plan, `Y' plan or the old type serks system which was used when back-boilers were installed. This type of system turns on your central heating at the same time as your hot water and is not independent whereas you can turn on your hot water without the heating.
Your new time-clock should have this option normally controlled by a dip-switch.
S & Y plans use motorised valves to control heating and hot water - does your system use them?
This particular clock is a fairly good one, I've fitted a few in my time.
https://www.screwfix.com/p/horstmann...ails_container
ETA: Judging by the wiring in the timer backplate, your system may be a Y-Plan (one 3-way valve to control c/heating and hot water)