Henry, your 1949 A7 has the earlier 7" brake, similar but very different in construction to the 8" brake on your B32.
BSA Service Sheet 212A from May 1954 contains a cross sectional diagram, poor in detail. Spindles simply unscrew (LH thread) and the cross hole in the end is a plain drilling, to take a tommy bar to unscrew the spindle.
As duTch suggests the spindle should screw in fully and protrude a couple of threads through the right leg without the wheel in place. My feeling is that the spindle is not made to the original specification, either a close but incorrect substitute, or a modified original part. Knowing the rarity of this model, expect spurious parts fitted back in the day to keep it on the road. As morris indicates, this may all be part of a bigger problem, so looks as if a complete strip and measure is the way to proceed.
The Draganfly Parts Diagram, as above, for the 7" brake shows a small spacer collar under a hub retaining nut, then the larger top hat sleeve which is drawn towards the brake drum side by an increased diameter step at the tommy bar end of the spindle. You indicated that the sleeve was originally the wrong way round, in which case it may be incorrect anyway. The end of the spindle O.D. should match the smaller O.D. of the top hat sleeve.
Ever helpful Draganfly have pictures of the parts, so you can see how your bits stack up. The original sleeve has a longitudinal slot to allow it to tighten around the spindle and grip it as the pinch bolt is tightened.
There is also a good image of the correct spindle, showing it to be a plain round bar, threaded to match the right leg, and with a change to a slightly larger O.D. at the tommy bar end. This contrasts with the later 8"hub spindle, which is plain for most of its length, then stepped to a reduced diameter to pass through the right side wheel bearing and hub sleeve.
So any part outboard of the left hand bearing is suspect, namely the small collar, hub nut, top hat sleeve and spindle. Looks like the top hat sleeve passes through the fork leg, and the picture should show a larger diameter at the end of the spindle pushing on the sleeve, rather than the decreased spindle diameter that appears.
Swarfy.