As I see it, while any agreement may be with the partners, Saudi Arabia is not averse to sharing it's information and technology with some of the UK's more agressive opponents.. The Japanese are well aware of Saudi backdoor connections and in my opinion, have adopted the correct approach to the project and ruled out accepting Saudi's contribution. It should not be all about money, unfortunately for the UK, any potential partners will leverage their greed to get what they want.
IG