The only 2 DLC UK routes I see in the store are: Cornish Mainline (TANE), and Settle & Carslile. The S&C is pretty old of a routhe by today's standards, but has some interesting features & a lot of rolling stock. Cornish Mainline I think has been updated & is built into '22 now.
There are a lot more European routes on the store however, I'm not that familiar with them however,
Edit: oh I forgot the ECML route for the UK.