The contract has now been published here
https://ec.europa.eu/commission/presscorner/detail/en/ip_21_302
Two key points stand out. AZ’s commitment is to use best reasonable efforts and the commitment is to manufacture the initial doses within the EU.
I think this reveals the EU’s claims for our vaccine to be groundless.
Section 5.4 Manufacturing Sites AstraZeneca shall use its Best Reasonable Efforts to manufacture the Vaccine at manufacturing sites located within the EU (which, for the purposes of this Section 5.4 only shall include the United Kingdom) and may manufacture the Vaccine in non-EU facilities, if appropriate, to accelerate supply of the Vaccine in Europe.... It goes on... and on.... but I think this is the relevant part.
I can see this ending up in the courts to see whose contract with AstraZeneca takes precedence, the EU or UK. It's been reported that there is a clause in the UK's contract that stipulates that AstraZeneca must fulfil the UK's order from UK manufacturing sites before supplying anywhere else and of course the UK/AstraZeneca contract was signed three months before the EU/AstaZeneca contract.
I wonder if the EU Commission bothered to tell the British Government about this clause or even ask whether it was OK to consider the UK part of the EU for the purposes of this contract? 
Which courts? Certainly not any European court and, I'm sure not any British court.
Good point. The ECJ has no jurisdiction in the UK, and their contract probably stipulates that it is governed under EU law. Unless..... there is a sneaky provision buried in there somewhere that it can be tried under English law as well. I wouldn't put it past them.

In other news, the EU Commission has today invoked Article 16 of the Northern Ireland Protocol restricting the movement of vaccine between the Republic of Ireland and Northern Ireland, a move Arlene Foster has described as
" an incredible act of hostility " It's kinda technical I guess as NI gets it's vaccine from the UK, and given it's shortage of vaccine it's laughable that the EU are worried that NI might be used as a backdoor to supply the rest of the UK. Unless they plan a blockade of course...

It seems that the EU comission are becoming increasingly unhinged... and what about the Good Friday Agreement?
https://www.bbc.co.uk/news/uk-northern-ireland-55864442