In the 80's Mgr of SF bike shop* was proud to have found a British winter Training Bike frame and fork .
From Well known builders, Mercian , or one of those , . Kit was A Fixie, rear opening to chain tension..
but the dropout was made for mudguard mounting, included Eyelet hole
wheel clearance adequate for fitting them, and places to mount brakes.

*site of One of my past Jobs.