From your pictures the mudguard/shroud clearance looks maybe on the large side, more often the guard almost kisses the shroud. The centre of the mudguard bridge/fork brace clears the tyre by at least an inch, and if the wheel rotates centrally should not catch on this or the guard.
Possible reasons for the problem are distorted or incorrect parts, incorrect assembly, even simply a tyre which although is the right size, has a different moulded profile from a 1950's example. Front rim was originally WM2 Profile, standard tyre 3.25 X 19.
Make sure the wheel and brake drum are located correctly to the right leg, spindle tightened, then that fork legs are aligned correctly, pumping the forks a few times to settle them parallel and checking again before tightening up pinch bolts and top nuts.
Other possible is a bent fork leg, often overlooked if the previous owner positioned the bent leg to point in or out, rather than front to back. Telltale sign on a bike with a diver's helmet cowl is that the line of the cowl rim is up on one side, down on the other compared to the headlamp, as the yokes are positioned for the best compromise position to disguise the fault. Yup, found this the hard way! Thought the cowl was wrong, no it was a bent leg.
Should be an easy fix, just a bit of detective work.
Swarfy.
