There need to be more available products that are compatible in the UK.
From my perspective the first would be light switches, and power outlets. Rather than having an add-on unit such as a smart plug in power socket or smart light bulb (that are ok for a quick fix/fit) but in my view look unattractive and deter from the smart home feel. I would rather have a unit that replaces the existing light switch or power socket, like the products available from Lightwaverf. (or make smart things compatible with them.) This way you have the option to control the light fitting rather than grouping bulbs. (again i think the smart bulbs look unattractive as well as being expensive per bulb). The power sockets speak for themselves. Rather than having a add-on product plugged into a standard socket, sticking into the room. A smart power socket can be recessed into the wall replacing the fitting and looking like it should be there rather than an afterthought.
Secondly, in the UK there are not many homes that have cooling units. (it doesn’t get that hot over here) therefore having a thermostat that only controls the room temperature gives little benefit until it get to the winter months, it would be better to have system such as Hive (or to have hive comparable with smart thing) that controls the room temprature, but also allows you to control the hot water, i.e. during the summer when the heating is never used you can still control the hot water system.