Having a "bunch" (what's the collective noun for bitcoiners?) of bitcoiners there would be the perfect opportunity. Imagine if half their customers that night kept asking "do you take bitcoin", "I'm only coming back when you take bitcoin"?
A hash of bitcoiners? We'll work on em, but suspect pubs in the centre of Brighton don't feel too threatened by a small group of geeks walking out ;-)
"Hash" = very good.
As long as the pub isn't part of some horrible chain (Wetherspoons), and the owner isn't some kind of luddite, you have a chance of getting him interested at least. *Every* business owner is looking for an edge, give people a reason to use them instead of the place down the road.