UK is a member of the EU ( well, for the moment) and thus they supplied a unit that meets the EU spec. I know that they should have at least sent a complimentary deathdaptor with a Shucko plug on the one side and a UK socket among the other side, but they probably also supply to Switzerland, and have to have a different adaptor, to France which almost is a Shucko type and so on, so in most cases the customer will end up with a big box of adaptors that are unusable.
They probably might also make the AC adaptor with the ability to have different country plug systems as a slide on and latch arrangement, like a lot of Japanese manufacturers do, supplying a plastic bag with 5 different plastic parts, that have in total 10g of plated steel as the current carrying bits, and which promptly gets 80% of them thrown away by the customer after complaining about having to figure out which one to use and how to follow the big fold out pictogram of how to install them ( slide and click, but wow how difficult) on the wall wart.
Here there is a type M socket, which is now official, though I have yet to see any appliance or device with a true type M plug on it, only thing they get used for ( and the reason I put them in a lot) is to have cellphone chargers neatly arranged, and to plug in double isolated equipment that comes with a 2 pin socket that fits them. I put up a few to run DECT base stations and repeaters at work, as that way the adaptors do not go "missing" for use in cellphone chargers, i got tired of buying a dozen every 3 months to replace them.