There's a couple of Large ones on ebay if they're any good? One an original replica by the looks of it and one Score Draw one Just keep checking, that's where I got my XL one.
http://www.ebay.co.uk/itm/Scotland-1986-football-away-shirt-size-L-/182128551703?hash=item2a67b52717:g:TJ0AAOSwvU5XNGx7
http://www.ebay.co.uk/itm/SCOTLAND-Score-Draw-Shirt-FIFA-WORLD-CUP-MEXICO-86-L-/182128666985?hash=item2a67b6e969:g:gQoAAOSwubRXNIhu