Help please......BSW 9/32" nut search

I know that feeling, I was wire brush sanding a Silens Messor handle trunnion and didn't take the nuts off. Unsurprisingly the nut on contact with the 9" angle grinder 4" twist grip cup shot across the garden, never to be found again.

If I've been after Imperial nuts, you may have a local industrial fastenings supplier in your area, but I find they only have metric and get snotty on selling one nut.
The various vintage motorcycle parts supply companies or any source online would be best in this instance.

Try EKP supplies - they supply quantity 1 nuts including BSW.  I've had a quick look and they didn't list 9/32" specifically, but if you message them they may have them in stock or can make to order.

BSF and BSW Steel Full Nuts - EKP Supplies - Precision Turned Parts for Model Engineering