Reality check.
UK industrial law works thus:
If the Union asks for the moon on a stick, e.g. 15% payrise plus a bucket of frills and benefits. Then the company at the end of the negotiation phase will ask for Binding Arbitration administered by the folks at ACAS. This means someone independent of the company and the union gets to choose the winning negotiation position.
If the Union has asked for a moon on a stick then the Company offer will be selected. No arguments - its legally binding.
If you ignore the request for Binding Arbitration then you had better have your legal ducks in a row, a very high and very committed union memebership and a willingness to take the company to the brink.
Just as we all know that lay enthusiasts know little about being a commercial pilot so the average pilot knows little about industrial negotiation and trade union law.
Cheers
WWW