jgxenite1,087 Locked 23 Feb 2018 23 Feb 2018
After entering the wedding venue, speak to the barman who will refuse to serve you without an invitation. Go upstairs to the rooms, speak to Bernard and say that he's not invited to the wedding - he'll then give you his invitation.
Return to the barman and then request the drinks in order from top to the bottom - when you receive the two pints of Sowerby Pumper, you'll unlock this achievement.