What the Union should be doing about it is simple. They should be handing management a proposal whereby all Easy pilots are employed on acceptable Ts and Cs as permanent staff or there will be a strike ballot.
Of course, the older guys on permanent contracts will stick their heads where the sun don't shine and not vote to strike, and then blame the union when they can't get a pay rise.
Just out of interest, what do BALPA charge flexicrew pilots in terms of membership fees. 1% of "salary" would amount to nothing wouldn't it, in your case? Get enough of you in and you will be able to have a ballot in which you can seriously influence the result.
Of course we have seen how BALPA reps fare in EZ...they morph into management. Same old, same old.