Ok, maybe we should try them. I also haven't ever been in Brighton earlier. I tried to find some underground punk sort of thing from the web and only what I found was a couple of years old notice board talk of locals in demand of a good pub to organize punk gigs in Brighton. Some mentioned a pub called Hobgoblin. When I checked their site it looked actually a nice place to go too... But it's good if the place is near to the venue too as mentioned (above).
May I ask where are you going to stay in Brighton? Our place is in Hove, East Sussex, and it's about 1,5 miles distance from Concorde.