That article's not correct - as I said above you can qualify as a HGP if you complete 3 seasons of football in England (or Wales) by the end of the season in which you turn 21.
By this metric, John Peter is a HGP.
https://www.premierleague.com/news/102383
Has Milner been confirmed yet?
Pedro (which is his middle name, BTW - his surname is Junqueira Jesus) is definitely a HGP, as he turned 21 during this season, which is his 3rd complete season in English football.