OK, here goes with my theory:
On a bike designed for ultra-close rear wheel clearance, it makes sense to have a rear-facing dropout - the wheel just has to be fitted in to the dropout slots, and moved forward as far as it will go. No need to fiddle about, making sure that the wheel is correctly aligned, as you would with a forward-facing dropout, and with the wheel spindle braced against the end of the track dropout, extra insurance against it pulling over. With a forward facing dropout, some allowance has to be made to move the wheel forward in order to release it from the frame, so closer clearance can be achieved with a track dropout.
The reasons I can think of as to why British riders would use road/path machines with track ends and mudguard eyes:
1. They could use the same machine for everyday use, club runs, grass or hard track racing, or short distance time trials. 2. Image. (As an analogy, who needs a 180 mph sports car for road use?). 3. Fashion - clubmates have one, so ride one to be part of the group. 4. Ride preference - the geometry of these machines is often different to pure road bikes.
Incidentally, machines inrended for fixed wheel time trials were offered by some makers with track ends, and some with forward facing dropouts.
Neil Foddering
Weymouth, Dorset, England