I think they had to change the design for the UK (compared with the US model), but it was more to do with the electricity supply than the boiler design.

Yeah they are simpler in the UK, no one cools their house for example ;)

Do you have an OpenTherm, modulating boiler (or kettle, as we call them here)? That would be awesome!

No I have a combi boiler, it doesn't store hot water. They can work with boilers though.