In the case of Kayal:-
His work permit hearing was on Wednesday January 28 2015. When approved, the required government visa from the Home Office was sought, being granted the next day. That evening (Thursday) the transfer was completed and the necessary paperwork was lodged with the Football...
All transfers (or registrations) of players who last played in a country/region covered by a different FA require international clearance (even at non-league level, and even including Scotland and Wales - Beram Kayal's transfer required international clearance).