1939 Sunbeam B24 350cc Classic/Vintage motorcycle - AMC Matchless AJS

I'm selling this bike on behalf of my mum. My dad bought this bike a few years ago but unfortunately passed away last month from an ongoing battle with cancer. I believe it's a 1939 Sunbeam B24 350cc. We have the V5 registration and a few bits of documentation, but not much about its history. The bike is in full working order but could do with a little TLC to tidy a few bits up like the wiring.

The bike would just need a battery to make road legal but could be ridden as it stands. I'd class it as an oily rag finish, not showroom condition, but extremely good for an 81-year old motorcycle. It shows 14,397 miles on the clock and shows good oil pressure from the gauge on the tank when the engine is running.
As I can't find any Sunbeams of this model on the internet for sale, it is very difficult to put a price on it and also shows how rare these bike come up for sale. I've tried some of the classic motorcycle forums but had such a variation in replies as to what people think this bike could be worth.

Over the last couple of days I've managed to make contact with members of the Marston Sunbeam Owners Club. They have confirmed that this bike is indeed on the VMCC (Vintage Motorcycle Club) registry and ‘The Marston Sunbeam Club' Register and their registers are now up to date on this bike. They confirmed that the Frame number, Engine number, gearbox, and Magneto are all period correct and from the same motorcycle. I was also informed that there are about 20 of these 350cc models on the registry making this a very rare bike indeed. Any questions please feel free to contact me.