Sold hundreds of these in the 1955/65 period.
And as a result you'll still see a fair few of these for sale. But even though you see them quite often, I'd say they are pretty desirable now. I've not noticed many 140mm ones though.
Anyway, I had been looking for one, until I got a Titan stem instead from a nice guy on here, so watched a few on ebay.
I remember one lot of two stems for sale with no nose bolts on ebay in somewhere between v. poor condition and the type of condition of yours is in and I think even that lot sold for more than 50 pounds.
Hope that is of some type of help. If I was you though I'd get it rechromed and keep it just cause it'd be so shiny and pretty! I'm actually going to send a stem off to get rechromed at a place offering a good price. I can show you the result whenever I get it back if it is something you might be thinking of doing?
Out of interest Keith, how much did the badged ones sell for back in the day? They are scarily expensive now!