Keep the West Kennet Long Barrow lay-by tidy!

We were intrigued to see this scary notice where we parked to visit the West Kennet Long Barrow yesterday…

especially as it needs amateurs, not the official site guardians, to think it is worth putting this very gentle request on the path leading up to the monument…

So which one is it more important to keep litter-free National Trust – West Kennet Long Barrow or its lay-by? If you think the former perhaps you could refrain from removing the amateur notice (which reflects the ASLaN charter, which we know you agree with) until you have replaced it with one of your own.  Thanks!