Shaun of the Dead vs Hot Fuzz vs World's End
Shaun's group
Vs
The Police in Hot Fuzz
Vs
Gary and pals.
Who would win?
Might have to say the police.
Shaun's group was mostly weaklings who would be destroyed in a real fight. Gary and pals have a lot of (I thought it's called) "Welsh courage" when they drink. Gary, Steve, and particularly Andy are good fighters (better than most of the police, maybe only Doris could fight evenly with them) but Nicholas would dominate that fight.
I see it as either Gary gets lucky against Nicholas or maybe Andy could take him. Otherwise Nick runs a train on pretty much all comers, especially with the other police as backup/bodies.