Bull notices the man, probably would have even if he was trying to hide, it is one of those things that happen with his training. Once the last of the supplies were inside he lets Des go about setting things up while he heads back outside. And then straight for where Wash is standing.

He left his axe in the inn on purpose and instead brought a bottle of beer with him. Doesn't hurt to make nice with the neighbours after all. That is what he assumes this guy is, he hasn't seen him much down in the south village so it would make sense.

"Hey."