Benair are operating two of these machines in the UK at the moment. Using them to run the mail around the north of scotland. However, these are on a danish register, but as you asked, they are currently being used in the UK for cargo operations.
Oh, and they run the aircraft two crew, and if I recall (wrongly), the LET410 is a bona fida multi crew aircraft. Apparently, it's the cheapest multi crew type rating on can do, something in the region of £4-5000.