The version I have been told goes as follows: A bunch of Aberdeen casuals started traveling down to London to get brand clothes that had not gotten up to Scotland yet on the regular. During those trips they developed friendships with Spurs fans and those that took to stealing the clothes rather than buying them also used the crowds at our pubs/the lane to hide from the cops. And our friendship grew from there.
No idea how correct it is, but it is the story I was told.
All explained in TTs book.