On Mar 1, 3:39*pm, John wrote:
The Church heating consists of three boiler systems, two of which have 3
and 4 zones respectively. This means I have two clusters of timers
(controlling the boiler via motorised valves) which is not too much of a
problem but it would be nice to have one for each of the boilers.

Sounds like you need some relays

It would also be nice to have remote "boost" buttons so users of rooms
can request heat for an hour or so (when I have forgotten to programme
it in) and preferably for the boost button to have an indication when
that zone is on.

Check elkay They have timer-only boost buttons, and timed boost
programmable thermostats, which allow the user to go from set-back to
boosted heat for 1 or 2 hours. They also have PIR activated versions
of the same.

As for on indication if that isn't provided it's a "simple" matter of
extending wires from the zone valve and fitting a neon in a
gridswitch.

Owain