however would you know what is being discussed by the various heads of state and government?
Are you suggesting that there are talks about the UK providing Eastern Europe with a nuclear umbrella?
he's got a huge and unassailable majority,
Which doesn't mean much when there is little he can do with it. Leaving aside that historically speaking, British PMs have a tendency of being taken out by their own party, like I explained above, the means of the UK are limited by its' position and budget restrains.
That majority won't help him on the issue of NATO and the EU, and it is my understanding that there are no plans of significanly increasing the aid for Ukraine either.
having served at a high level
Which experience does he have on the diplomatic stage? Or indeed at the highest level of governance, e.g. a minister?
Those are the things that are usually considered when head of governments are talking with each other. A leader like Macron whos has spent several years at the highest level is naturally at an advantage there.
Macron, Starmer, Merz, Tusk, Meloni are all on the same page. So are Korea, Japan, Canada, Australia and NZ, Czech,Romania and all the Baltics
Would be great if that was the case. But Tusk is now being sabotaged by PiS, Italy is doing little to actually support Ukraine with their ressources, Korea refuses to provide Ukraine with weapons (while NK is fighting for Russia).
Rhetorically they are on the same page, but whether or not that materializes on anything meaningful remains to be seen.
Maybe I am too pessimistic here, but the Western track record is really not all that great when it comes to Ukraine.