Dean Tweeks as mentioned have stock of most tyres. If you're looking for track only then I wouldn't bother with Federals or 888's. Get something that's Motorsport only. Have a look at the Dmacks, epic tyres.
Our next choice will be dz03g if we dont run full slicks, i have a contact for the dunlop supplier for the clio cup series, but im not sure on lead times
Car goes on a trailer and hardly use on the road, if I do I've got wheels with road tyres, not allowed to use full slicks, and they have to be msa blue book approved, need to get something sorted today so I get them tomorrow in time for Wednesday track day before Mallory race at week end.