Pokémon wholesalers for preestablished stores?

Hiya I work in a premier store (UK) and my manager wants to bring in Pokémon cards but our current retailer doesn't ever have them, we have the funds to do a large first order (as most wholesalers seem to require) but I've only ever bought as a consumer so I have no clue where to start, any recommendations as all the post I find about this are based on starting up a new card store not one that is preexisting