Hi
Doubt it can be enforced.
In fact I'd hazard a guess that there is absolutely no-way it can be enforced.
And yes, visit Sywell. Very sensible place, as the photo below taken whilst competing in last years Helicopter Club of Great Britain Air Games demonstrates. This was taken only 30 minutes after I was accosted at Halfpenny Green airfield for not wearing Hi Vis.
I was then accosted by Mick -for wearing one !!!!
