:bowdown: thankyou, and indeed this one was a taxing one. I knew it was genuine, but I hadn’t recalled seeing it in the team photos in the pre cup final period. I’d worked out that it must be a prototype/sample shirt, and then got to searching out the team photo in the cup final program...
He tells me he got it via the mother of an ex player back in the day. Its definitely authentic Adidas and of its age. I’m guessing it’s a prototype that was made up in preparation for the 83/84 season but was not actually used.