Mk3 Twin rear wheel bearing kits

[vana mana]

Is there anyone on here that can tell me....
Was there only 1 make of twin rear wheel axle /drum set up for twin rear wheeler mk 3 s
I'm really confused
I'm making a folder on Mk 3 part numbers and buying spares for my rear twin wheeler Amby camper

I've been using Ford 7zap...Fordopedia and catcar for part numbers
So....
Today I thought I would try track down as many part numbers... Cross referencing ebay sellers numbers against Ford 7zap... catcar... fordopedia.

So I see an e bay seller with a FAG make... Part number FAG 713678420
I also see this part number pop up as cross reference with other sellers alongside the Ford 7zap diagram number of 5015650
I message the seller and he asks for my vehicle Reg.. I give him it but he replies it won't fit.?

.... I don't get it... As his number is listed in other sellers listings alongside the correct Ford number.... 5015650?

Was there more than 1 twin rear axle for the transit mk3

Any help appreciated

Thank you