Kinesis T2 or TK3, plenty of clearance for tyres up to 28c with guards. The definitive UK winter bike.
Forme Longcliffe. Clearance for 25's with proper guards and another great British bike/brand.
Giant Defy, I ran my old one with 25's and "proper" guards ok.
If you want an old school steel club racer type winter bike, check out the Raleigh Clubman or the Eastway ST1.0. Neither is at all light, but proper clearances, steel frames, big tyres and full length mudguards make them very winter proof.
Or do as increasingly more people are doing, get a CX bike. Longer chainstays make more sense on winter bikes anyway, and you can run 28c or bigger tyres comfortably. Weight will be higher than a proper road bike, but not stupidly so.