This is a bit late but i got the code twice, first one i received from the Legendary tier from PC Gamer Club thing and another one from the magazine itself that is NOT UK only... i know posting a link is not allowed but there is a website called myfavouritemagazines that is located in the uk and ships out PC Gamer magazines world wide that include those codes, so if you ever want a physical version with the code just check that website out.
You can buy a subscription from that website for PC Gamer but you can also buy single issue. For me it was €9,99 including shipping not sure what the other prices are for word wide.
7th Year of Gold Premier Membership
2013, 2014, 2015, 2016, 2017, 2018 & 2019