The Sala BHP is the former Health and Safety building where the 21 demands were signed off and where strikes were coordinated. The hall has been left exactly as it was then but now also hosts an exhibition on the shipyard, with models of ships it once built and a section on its fate today (it's now owned by a Ukrainian company and makes wind turbines). To reach it you pass through the original shipyard gate the workers once streamed through.
The Sala BHP has a pleasant cafe and is almost always deserted.