This is a boiler care cover for £9.50 a month with homeserve but instead of selecting a free annual service you can select a tado smart thermostat worth £249.
Note this is the first generation tado and not the new one but the functionality is pretty much the same. The tado links to your mobile and turns the heating on when you are at home and off when you aren't. You can also control your heating manually via an app on your phone.
You can self install the wireless thermostat in about 20 mins with the online guide from tado and away you go.
The boiler cover from homeserve includes:
Central heating and a few other things.
Negative points to note:
Homeserves ratings for customer service are pretty poor
There is a clause that if you cancel your homeserve cover after a year then a rental of £3 a month is payable to tado, this can be cancelled but then you only receive basic functionality from you tado (from various calls I think this means you lose the location detection and are just left with a wireless remote thermostat)
I may be wrong in exactly what basic functionality means so please check first but as someone without an internal thermostat before this was a way to get at worst a free wireless thermostat in month 13 and a smart thermostat for the first 12 months (fingers crossed it's still smart in month 13 but can't be sure)
Note - there a slight possibility of £101 Top Cash Back too. - top cashback advertise this for the homeserve8 policy but doesn't mention the tado, it may work it may not but worth going via TCB if your interested just in case