Dallison was released by Arsenal so they have done the groundwork similar with Hall at Motherwell Walton at Plymouth, and to a lesser extent Hornby-Forbes at Fleetwood and Aderkugbe at Vancouver Whitecaps.
Not THAT similar:
Hall wasn't released by Motherwell.
Walton wasn't released by Plymouth.
Hornby-Forbes wasn't released by Fleetwood.
Adekugbe is still a Vancouver player.
I am sure there are some released by the Manchester and top London clubs who we miss out on like Henri Lansbury started going out on loan to clubs from Arsenal when he was 17 and signed for Forest when he was 22. This is the type of player.
Lansbury wasn't released by Arsenal. Forest paid over £1m for him.
Apart from that, great post.