Matt
Thanks for asking, being keen on making this period, I wanted BSA brakes and sourced a pair of 8" half sided front hubs (early A65 finned) , pressed them apart and had a new centre made that they are pressed onto.
So I've got double sided sls, with leading arm which is what you'll see on images of the daytona race BSA's as distinct from the brake lever to the rear as used in road BSA's
Its not suitable for a solo (weight!) but perfect for the chair. will probably ventilate brake plates in due course but no immediate need to tls it.
The blanking plugs have all been taken out and there is air flow between the two sides
I didnt want the later excellent 8" BSA/Triumph type TLS brake from the late 60's as it didnt look period and I wanted to retain an authentic 1955 vibe, given these later half width brakes are almost identical to the goldie hub of the fifties.
The dual brake arrangement fits just!
It may only be a norton but racing sidecar pic's always appreciated.
Tim