It was BALPA that coordinated the best legal minds and financial power of its members to defend the core principles & data in the accident investigation process. The alternative would be Pilots & their families, etc. providing a 'no comment' interview to the AAiB - it was a landmark ruling with international impact
The legal and practical assistance provided by BALPA to its full members is unparalleled anywhere else in Aviation. This extends to Pilot injuries & accidents, etc. around the world whilst on duty. In terms of experience and legal fire power in a world that wants to find the nearest 'guilty party' its second to none.
Shoreham IMO was a complete failure of the CAAs & UK obsession with light touch regulation. People & organisations don't do what you don't check.