Paddington 2 (2017 Paul King & co-scr)

A rare sequel to out-do the original, partly down to Hugh Grant's film-stealing performance (though Brendan Gleeson is particularly funny too). Script (with Simon Farnaby) and visual design more interesting, arresting train / chase scene (which just makes you think how incredible people like Buster Keaton were doing it all for real).

To answer my own question, it looks like the live actors acted to stand-ins, but not to Ben himself. More here.

And ultimately, it led to this...

... which was written by Frank Cottrell Boyce, Jon Fraser and James Lamont.