There are enough to make this kind of format work, and as you've responded elsewhere it doesn't mean you lose 48 riders who ride on the continent.
It may mean you might see more guests or sides opting to run on a night which best suits the riders they've signed up
Nobody is going to run on a Sunday with anyone who rides in Poland but some clubs opting for Tuesday, Wednesday and Fridays may have some wiggle room if fixtures allow with what the danish and swedish leagues are up to
There are insufficient riders is an easy out, its not, it will allow for more opportunity for homegrown and perhaps riders from the commonwealth