A small follow up. Taking ianmcd advice putting the boiler on constant the thermostat works perfectly. If I switch back to the boilers internal 24 hour timer the thermostat doesn't appear to be able to override the internal timer.
Thanks for the replies guys. food for thought, I'll have a read up in the manual. It was installed by a work colleague of my stepdads where he was working at the time. I've tidied up the wiring and clamped everything properly. I've uploaded a image of the boiler.
Looking on some advice for my parents if the boiler and thermostat are wired up correctly?
The boiler and thermostat were both installed around 2012 and I'm not sure if the thermostat has ever worked correctly. Any time my parents have wanted to increase the temperature in the house they've...