What all this highlights is that in the UK we have a chaotic lack of a system for determining whether or not we can use a particular aerodrome. The only law that I can determine is that one must have the land-owner's permission to use that land. This might be a 'blanket' permission making everyone welcome without any pre-condition or radio call (I've landed at more than one strip with no-one in attendance or ANY kind of specific permission simply because the land-owner has let it be known that one can do so) right up to the other end of the scale where anything short of a full emergency, hell will freeze over before you could get in with a SEP. It seems in some parts of the world, you just call a few miles out and in you come (can't believe that REALLY works at EVERY aerodrome in the United States, but that's what some people seem to suggest).
Personally, I always call ahead by phone just to make sure the place is open, weather's OK etc. Sometimes they just say 'don't need your details, just call on the radio' but at least I've a reasonable expectation of conditions. That's notwithstanding that the aircraft in front of me blocks the runway with a burst tyre causing me to divert to my planned alternate, of course!
Ref. Biggin Hill, I've been flying in and out of the place for the past 35 years; mostly for maintenance and it's always been a busy place needing some planning and forethought. I've never seen it as a place where you can just say 'oh, I think I'll pop across to Biggin on the Bump for a cuppa'.
TOO