This is a Seiko 6319-508A from 1979, bought for as little as lunch money I could see potential past the badly scratched crystal so bought it with a view to sell. Once I had polished the case and replaced the crystal the watch was looking a lot better. Lucky to have found a new old stock crystal in this one!
The leather strap it came on was clearly home made and 10mm lug Seiko bracelets are not easy to acquire.
I found a 10mm lug bracelet I had from a parts watch and put on this watch to finish the look. Now on the wrist I think it looks fantastic.