There are so many different pieces to this question, it’s a little hard to know where to start. So let me just take one piece at a time and forgive me if they don’t quite all fit together.
First, the answer about zigbee is depending on the profiles:
Second, the specific question about zigbee home automation (ZHA) repeaters for the UK is that people were using the Orvibo relay, but now that product has been discontinued. 
And the xiaomi pocket socket has turned out not to be a good repeater, not totally surprising because it’s not certified.
And the smart things pocketsocket has turned out to have a fusing problem, and appears to have been withdrawn from sale, but without a replacement device yet. ( This only affects the UK model)
It should be true that any ZHA pocket socket would work as a repeater and for basic on/off with SmartThings, although it might need custom code if it had other features like energy reporting.
Right now the only one available at Amazon with the right certifications is the following:
https://www.amazon.co.uk/dp/B01B5P5Y6S/
But I haven’t yet seen any reports in the forums of people actually trying it. Most people seem to have switched to the less expensive Z wave pocket sockets as a substitute for the SmartThings branded device, which work well, but won’t repeat for zigbee.
Securifi makes the zigbee “peanut” pocket socket, but all the listings I’ve seen are for the US model, so it seems to be difficult to find the UK model.
Develco makes A mini smart plug for the UK which is ZHA and should work, but it’s outrageously expensive at over 60 pounds and you can only buy it as a sample from them, no returns. So I’m not happy with that, but I mention it just for completeness:
So right now, I don’t really have a good answer to this question. You could try the hive and let us know if it works since Amazon should have a decent returns policy if it doesn’t.