Try these people they were great with BSA and my TR25W when they were in their old shop. Not visited the new place but if they took all the stock with them I bet they found some good old bits in the loft, that even their father didn't know were there !!
C & D Autos (BSA Spares)
Barns 6-8 Tracy Farm
Redditch Road (A4189), Ullenhall Henley in Arden B95 5NY
01564 795 000
Alternatively there is good ole
Vale-Onslow L H Ltd
116 Stratford Road
Sparkhill, Birmingham, West Midlands B11 1AW
0121 772 2577
Never know what this emporium might have out the back .,.. I do know they still have the square 1968 fibreglass side panels. I got mine from there and there's a pair still in the window.
Len VO god rest his soul claimed to be the UK's oldest working man still at it at 90 odd. The sons and grandsons still own this emporium which if you can get there is worth the visit to step back to the 60's into a shop that hasn't been decorated or updated since. The company goes back to the 1930's when they assembled their own model machines from the best bits around called unsurprisingly Vale Onslow Specials !!
Regards Gromit