Help boiler timer replacement

Cornucopia

Another option could be to replace the room thermostat with a digital timer based one.

Like this one that I have on my wall: http://www.screwfix.com/p/iqe-7-day-programmable-room-thermostat-with-li-ion-battery-back-up/53575

Le_Kirk

Have a look at this link. It shows about half-way down, the following text.
Replaces (same back-plate and wiring for easy swap over) RWB1, RWB102, RWB2 ......