Hmm, I'm in the EU and still get hit with customs charges from Chinese items e.g. AliExpress stuff. Not sure if there would be British-made equivalent.

But I'd sooner order from a company that is liable e.g. if the IoT device burns down my house.

AliExpress charges VAT now.

If your IoT device burns the house down your circuit breaker failed, or you connected it without proper failsafe measures.

Is it burning it down by being on fire itself, or by turning something on that shouldn't be?

Surely a breaker can only detect over-current or short-to earth/neutral (which would also be an overcurrent I guess).

If the thing just heats up and catches fire, it might not trip the breaker. I meant overheating itself, not erroneously turning things off/on.