I have the feeling BASSA wants to strike and not come to a conclusion in the beginning. This is based on what has been said on previous union meeting and on one occassion they said they would strike but weren't sure of what at the time. Many of the crew also want to strike as this is the jargon amonst the community.
I doubt BASSA would approve EF to operate WW on EF Allowances. In such case operation in terms and conditions of WW Allowances, length of rest and MBT would apply. I don't think this is applicable either now as traffic is going down and crew are being offered part-time and UPL.
Again, I would be surprised if BASSA approved. Especially when you think that the company has to ask them for permission if WW can do a EF trip or vice versa or WW can work one down out of LHR. I remember the snow storm earlier this year and we were one crew short but the entire crew prepared to work down as flight wasn't full. BASSA said no.