Storm in a teacup. The guy is clearly a muppet and needs put back in his box, but….
Multrees Walk is private land, not a public footpath (found all this out years ago when a friend got some security guards stroppy with him for taking photos). There is no difference whatsoever here to cars driving over a pavement to access a driveway. None. It's private land, the landowner can allow people to park there, and because it's legal parking they are allowed to access over the path outside which is public.
Not your usual parking on the pavement. All legit, above board, legal (including the driving there). And if anything there will have to have been risk assessments carried out by the company doing the promotion, and I suspect taking the cars on and off, as well as being at much quieter times of day, there will have been people herding them on and warning pedestrians, so actually safer than anyone parking on a driveway.
I happened to walk past them too. Two Jag F Types. Lovely cars, and despite being from the same stable I think a bit prettier than the Aston cousins. Can't say it even crossed my mind to complain about it, but then I appreciate the aesthetic and thought they improved the bland grey passage (plus there was LOADS of space to pass on either side - wish I'd taken the photo I wanted to now).