Nigel, if a runway was being used for a purpose such as testing race cars, that would certainly render the runway unserviceable, and as such would be NOTAMmed for any certified/licensed aerodrome..
Perhaps it is Kemble's experience that the sort of people that pitch up out of hours, don't read the NOTAMS either
In fact, general UK GA expeirence would suggest that the NOTAM system is not a good way to keep things safe (both the lack of people bothering to read them, and the poor facilities in being able to read them).
If its a private aerodrome, they'd tell you when you called ahead for permission to land, and you'd plan accordingly
They told him the closing time when he called ahead, but he failed to "plan accordingly". Once they are closed, there is nobody to "call".
We don't tend to have "public" aerodromes here, apart from a few Govt/Military ones... they are all "private".
Kemble is a busy airfield, and effectively "industrial" complex, with numerous businesses operating, including using runways etc. PPR etc. might be over used at some airfields, but Kemble is not one of them IMHO
NoD