I remember a cup tie when Rangers played Stenhousemuir. A gang of Rangers players bundled the Stemnie goalie over the line and Beaton gave a goal. After that he was generally known as the best referee money can buy.
Looked like he ignored or overruled the linesman flagging for offside when the lino was in a far better position than him. He also didn't enforce the new sub leaving the pitch rules.
Irrespective of the off side you cannot criticise hime about the sub rule unless you avtually have read and understood it. Rhe referee retains discretion where the players leave the pitch. If you dont believe me go actually read the rule.