I saw that earlier Torch and had a go. But there was something wrong with the link as I typed in Man City (sorry to give one of the answers away) and it accepted it. I then typed the name of 3 more teams in, and double checked the spelling, and it wouldn't accept them.
When I clicked to reveal the answers, the 3 I wanted to add were there! Think with those 3 I would've got to about 12 as well.
19/21 missed a couple of obvious ones but thought I already had them all - was convinced of Oldham and Millwall instead, no idea where they came from. I guess I'm just too old!