We're thinking of getting a Hive remote-controlled central heating
controller/thermostat so we can set our heating to come on several hours
before we get home from holiday etc.

I'm trying to work out whether we need a single- or dual-channel controller.
Hive's customer support was di they wouldn't offer any advice and just
said "speak to a qualified central heating installer". Imagine not being
able to offer any pre-sales advice!

We have a combi boiler which currently has a dual-timer: one for the central
heating and one for the hot water. The hot water is pre-heated in a
reservoir in the boiler, hence the reason for being able to time when that
pre-heat comes on and off, so it's not wasting fuel keeping the reservoir
hot overnight.

Hive say "single-channel for combi; dual channel for conventional boiler
with hot water cylinder". Our system sounds as if it has some features of
both: it's mostly heat-on-demand but with timed pre-heat of a small
reservoir in the boiler.

So, single or dual?