It was the reference to the da Silva's really.
The whole system has been restructured since, with a kind of points based system used. There are points for wages, transfer fees, the club you played for etc.
There's a version of the (current non-EU) points chart at:
https://latitudelaw.com/news/the-fa...s-and-possible-implications-following-brexit/
The PL have asked for the rules to be rewritten to say that if you've been given a PL contract, you can have a work permit. The FA will probably confirm that with a proviso that no club can have more than thirteen foreign players.
Incidentally it's the FA/PL who are essentially the authority on this. The convention had been for the government of the day to accept them as the professional qualifying authority. Which leaves the immigration service role as being one of checking the other criteria - like criminal convictions etc.