What i want to know is; is there a better/cheaper alternative room stat
(24
hour version is fine, 7 day version is even better). And if there is, is
the
wiring likely to be the same?

Almost any wired programmable room thermostat will have simple contacts and
are wired up in the same manner. A very few have permanent L and N for
power, but the overwhelming majority are battery powered using latching
relays.

There's a huge variety of designs to choose from at various prices,
appearances, sizes, shapes and features.

Christian.