Helen have you actually read this amendment?
You say J class is a contractual promise...how about this little gem...
"staff contractually eligible for J/F, travelling on flights where there is no first class, are booked economy with upgrade to business if space available"
How exactly does that abide by the "confirmed J class travel" part of your contract?
This whole amendment is full of holes....and regardless of what people think of their entitlements, raises more questions than answers.
It also quite clearly says, if the flight is full, you may not get your entitled class "until at the gate or the lounge" How does that work in with your contract?
It also says if, after turning up at the gate, they decide you have to travel in Y, then you're stuffed. You get no compensation. I guess at that point you could offload yourself, but how many people are going to do that at the gate?
I think everyone needs to write to JA or similar and have this clarified. My reading of it means there is going to be a lot of problems at check in until this is cleared up