Americans do not require a visa to travel to the UK. They only need a work permit if they are working in the UK. While the Cardiff GP is in Wales, the riders are paid from Geneva therefore are not working in the UK.
The big question with Laguta is when did he apply for the visa. He has had 8 months to work this out not the 9 days that the guys riding in Balakovo had last year. Out of the 9 days, 4 of them were weekends. Also just for the people who ask, Emil would be traveling here on his Polish passport.