The Mariner in pwllheli has sky sports.i think the owner was actually a city fan as well, but I'm going back a few years. Only a smallish pub and its down some stairs, nautical themed.
If you head the other way then in criccieth there is the bryn hir arms with sport.
From the haven site you can get the train there and back if they are running. You have to go left out of the main site then left again to get to the station penychain. Also busses run usually fairly regularly from the main haven entrance.
The Bryn Hir in Criccieth is a very decent pub. Pwllheli is less attractive. Trains are every 2 hours...not 1. Very limited service.