While wearing Hi-viz is no big deal and carrying enough for every passenger is also no big deal it is a pain in the @rse. The AIP entry is not 100% unambiguous. If it's good enought for Heathrow Gatwick & Stansted to have pax crossing from terminal or bus to aircraft without hi-viz it ought to be good enough for Kemble.
The problem is that pointless "safety" rules produce a fog that obscures the real issues. Pilots are required to meet a standard of visual acuity that allows them to avoid driving into things. The tower at Kemble is painted a sort of yellow (though I doubt the actual colour complies with BS EN 471) so I suppose we're unlikely to drive into it. The railings round the parking in front of AV8 are deffo non-compliant though. That said, it's Kemble's owner's prerogative to set the terms under which we are permitted to play with his toy.
If he demonstates that he doesn't understand the requirements of CAP 642 then he shouldn't be surprised if people decline to use his facilities.
Mike