Certainly the UK MHRA have been working closely with the companies to move the process along very quickly, as has been confirmed by both the government and the companies themselves.
I'm curious to know what's really going on at the Halix plant.
In the absence of further guidance and given the EU's hostility to them so far, AZ may be waiting to ensure it has all its ducks in a row before submitting.
In the UK the regulator was willing to do partial processing of applications in parallel with the project being executed, which isn't normal and poses obvious complexities, but can speed things up when latency is what matters most. If the EMA hasn't indicated any willingness to do that, and it's not the first time they've come up with this "we're waiting for submission" business, then it may be causing artificial delays.
It is in AZs interest to not start the process which would make the factory available for EU, where AZ is not willing to deliver at this time. (Instead, they ship doses even from the EU factories to UK and elsewhere.)
Given this, you would need something concrete to back your speculation to the contrary.
It's not in AZ's interest to keep an expensive factory idled in an environment of unprecedented demand, obviously. They want to sell vaccine to whoever will take it. AZ is "unwilling" to deliver to the EU because it has signed contracts putting other countries first and they are able to consume the entire supply. Once the UK is done, they will suddenly become "willing" (if such a term makes sense when contracts are involved) to deliver to the EU as well.
So to be clear, you are describing factual statements as speculation (which is wrong) and then making spurious claims about AZ/EMA's claimed interests instead of what they're actually doing.
"Rolling review" is the term I've seen typically used for the process that you described, and Wikipedia has references for various rolling reviews by EMA starting with the following: "In October 2020, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) started 'rolling reviews' of the vaccines known as COVID-19 Vaccine AstraZeneca (ChAdOx1-SARS-CoV-2) and Pfizer-BioNTech COVID-19 Vaccine (BNT162b2)." https://en.wikipedia.org/wiki/History_of_COVID-19_vaccine_de...
Relevant quote:
Asked about the Halix situation, the commission said on Friday that the EMA was ready to fast-track authorisation of new production facilities once it received an application and the necessary information from AstraZeneca.