Pblakeney
Shaman
I think Burnham is 'putting FoM out there' as 'something to discuss' to see what public/press reaction is. That would be the biggie that would unlock a lot of goodwill with the EU, if accepted. I suspect Burnham would tie that to 'small things' that would be noticed as tangible travel improvements such as free mobile roaming and using EU gates (if practicable).
I'm getting the impression that Burnham is quite canny on finding things that have been lurking in people's minds as annoyances which they've kind of put up with, and by picking them off one by one, he's changing people's 'grievance priorities'. Give them something positive, and they are less likely to be open to the manufactured outrage of people like Farage, who thrive on grievance.
...all while taking the microscope off the budget. All very canny.