I think that the Association will have zero impact.It doesn't have any say on pay rates and leave problems within CAD.The pay and leave can only be dictated by the Civil Service.
One solution would be to hire expats to fill the gaps,and get more bums on seats.The pay issue is in the lap of the Civil service gods.
There are a lot of places facing double digit percentage traffic rises with nothing for it.How are you going to stop more traffic?It just appears.
More expats is the only short term fix.At least the locals would get leave as well,and it is possible within current Civil service rules.