No pretty. Best endeavours is not as binding as guaranteed delivery. Guaranteed delivery type contracts are better for the customer (it therefore sounds like the uk have better terms than the eu)
David Allen Green was also saying that an english court is unlikely to rule that any failure in best efforts should affect other contracts. In other words it cant force AZ to break contracts with others in order to fulfil obligations to the EU. AZ may be in a situation where they simply cant fulfil both contracts, in which case they have to decide whether to fulfil one at the expense of the other or break both. Remembering if they break both they could be sued by both.
Its part of the reason the Eu wont sue. Because it is unlikely to make any difference to whether they have vaccine and will merely push the price of vaccine up. They don't win either way.
In reality they have made a stink because they haven't really got any other options. It leans on AZ who will have to bend over backwards and try and come up with an alternative solution.
My best guess is that its probably coming from another rest of the world factory at the expense of someone else rather than the uk. But AZ will want to keep very quiet about where and who may be affected.
I note here that if vaccine is being taken from uk production then the uk government will know about it. They then have the option of creating a stink. It may or may not be worth it. But the chances are it would be picked up / leaked and that wont be pretty. So thats why i don't think its the uk supply affected. I genuinely think it would cause unrest here and be politically destabilising in various ways. It is effectively an issue of national security its that serious.
The Eu blowing up an issue in that way is not good, healthy nor in their interests.
Equally though if az did break contract it would be interesting to see what the uk government would do. They could also threaten action... Thats how it spirals out of control.