To your point 3, Belgium may well have great logistics but the UK government has knowingly undermined and compromised UK logistics (the whole industry is crying out) as part of their Brexit process.
Maybe there are extraordinary arrangements being made for the vaccine, but it won't be because of a good prevailing open-market logistics situation.
Your comment has nothing to do with the logistics of rolling out a mass vaccination programme, but how exactly have the UK government’s Brexit negotiations “undermined and compromised UK logistics”?
Negotiations are ongoing to secure a trade deal with the EU once the transition period is over. The UK are also securing trade deals with other countries, including Canada and Japan.
Both sides recognise failure to reach a deal, or to extend the transition period, would be damaging for both sides.
Which is precisely why both sides are negotiating a deal to ensure that doesn’t happen...
Which I now realise I misread as "Developed in a country" (i.e. Belgium, where it's manufactured). An entirely different, erroneous, reading of the sentence.
Therefore my comment addressed the nature of cross-channel shipping which authorities I respect have repeatedly warned about.
It's too late to edit to add that clarification about the misreading. But that's what was missed.
If the army steps in to provide logistics at a time of national crisis, that's great. But it's not what I would expect this government to do based on the recent historical evidence: We've been in a national crisis for a while and the government has routinely preferred to neglect public-sector expertise and go private in a vast array of public procurement. Much of it has been highly questionable judgment (ministers awarding contracts to friends with penalty clauses).
Maybe there are extraordinary arrangements being made for the vaccine, but it won't be because of a good prevailing open-market logistics situation.
Edit: here's the Road Haulage Association warning of severe supply chain disruption https://www.bbc.co.uk/news/uk-54021421
Edit 2, since responses are unexpected:
> HMRC's assumption is that there'll be 11 million new customs declarations a year on goods going from GB to NI as of January 1
https://twitter.com/adampayne26/status/1334073058815074304