Yes this is all useful, and much as I suspected. I have been sent copies of the original registration entry which was indeed Chester. The Austin Seven Ruby I am restoring is extremely original and is the earliest known example still to survive. The money spent will never equate to any future sale price, as is usual for old car restorations these days. A very similar reg is available for £2k and I suspect that if I ever did contact the current owner of BMA139 it would cost at least that or more to purchase.
To have the original reg back on the car would be the icing on the cake but most likely will never happen and I couldn’t afford it if it was ever possible. But I do feel the need to make every effort to at least try to locate it. I did say it was a shot in the dark!
I am very grateful for all the replies and comments.
And I might yet get lucky one day.🤞