https://en.wikipedia.org/wiki/.uk#Second-level_domains?wprov=sfla1

Until 10 June 2014 it was not possible to register a domain name directly under .uk (such as internet.uk); it was only possible as a third-level domain (such as internet.co.uk).

Perhaps these sites were registered before 2014…

The weirdest “UK company” domain I saw recently was in .uk.com