clubman 

Many vintage mudguards, Bluemels for instance, will fit most wheels. The effective outside diameter of the tires on 26"/EA3's and 700c are virtually the same. 27's aren't much larger but a few issues can crop up, like width of the mudguard vs frame specs like bridge placement and clearances for seat stays and fork crowns.

Sometimes you've got to McGyvor the crap outa them.