Dave, the hanger in your photo is not the "B" type, look at MO21 in the spares list (blue book) and you will see what one looks like. Looking at your photo I am not even sure that what you have is even a Vincent hanger, looks a bit home made to me as both the top and bottom are the wrong shape. This link is from the VOC spares shop and shows what F52/17 should look like but without the slot for the gear lever (not sure why they have not shown a photo of the hanger with the slot). (
https://vocspares.mamutweb.com/Shop/Search?q=F52/12&page=1. I don't know what you paid for one from
http://mikesindianparts.com/VINCENT PARTS.htm but they look like they need a lot of work to look good, personally I would have bought one from the VOCSC.