Careful you don’t disappear down a rabbit hole here. There’s absolutely no evidence of vaccine from AstraZeneca in Belgium being sent to the UK, and nor is it at all likely to have occurred. Unopened multi-dose vials of the Oxford-AstraZeneca vaccine have a shelf life of 6 months, and that’s one of the reasons they took a chance and started manufacturing it in the UK many weeks before trials concluded it was safe and effective. If AZ was working to its best effort it will have been manufacturing as much vaccine as possible to be ready to meet the EU order as soon as it was approved.
https://assets.publishing.service.go...eca-reg174.pdf