It's interesting how people can put slants on votes like this. If the vote was No - 3,449, Accept - 1,686, Abstain - 4,622 (based on a quoted membership of 9,757 from above) then possibilities are:
"Only 17% of members voted to accept"
"83% of members did not accept the offer"
"65% of members did not vote to reject the offer"
"Only 35% of members voted against the offer"
"67% of votes cast were to reject the offer"
"Only 33% of votes were to accept the offer"
Pick whatever suits your agenda and run with it
FWIW (and I have no brief for BASSA whatsoever) I've very little time for abstentions and am generally of the view that if you abstain then you are implicitly accepting the decision of those who bother to vote.
This ballot says to me that 67% of those with an opinion they can be bothered to register don't accept the offer. Quite why they don't, and quite why nearly half of the membership of a union branch involved in an acrimonious dispute can't be bothered to vote are both beyond me.
Own goal from the abstainers IMHO.