I have confirmed this with Colin Andrews personally, who verified it all. And yes he has photos in his archives, which (I believe) have never been released. I do not doubt him as I know his work with the British government from listening to him talk about it the past 15 years.
He has photos of the ones that appeared on Major's grounds and Prince Charles' grounds, but believes none were taken on the Queens grounds.

You'll have to take my word for it (and his), as I won't disclose what he told me off the record. Besides, you folks here wouldn't believe me anyway. Some of it is shocking, but seeing as you all think it is being done by two drunk old men with planks of wood at their feet and guide holes on their caps, any attempt at convincing you would be a complete waste of my time.