h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I was reading a very uninteresting tome about the "disappearance " of Lord Lucan by the Scotland Yard inspector who was in charge of the case. In the foreward of this literay masterpiece I was impressed to see that he was also in charge of the case of the missing aforementioned stone. Needless to say, after reading that this gentleman of the constabulary was convinced that it las a lone radical Scot that was responsible for this heinous crime, I returned the book to the library forthwith, unread of course. The reason for my cynicism being a story related to me by my dear mother about a "friend" of the family who , (with a group of friends), while as a student was involved in a little larceny from a small chapel in the middle of London. Whether the stone that was removed was the original is anyones guess, the one that is there now it would be safe to say is as bogus as an Aberdonian philanthropist.

A single thief of the stone! What a strange idea. I thought it was a well known fact that it was a group, what with some of them being arrested and confessing to the whole thing. Whither they returned the one they stole or not, and whither it was ever the real one, is the answer we would all like to know.

If it is not the real stone in Edinburgh then where is the real stone hidden. "Let us consider the facts" as they say on one particular TV program.
1: One of the people officiating at the crowning of the Bruce (last Scottish king crowned at Scone) was the Earl of Strathmore.
2:The Earl of Strathmore lives 20-25 miles from Scone.
3:His castle has a secret room.

And do we know what is it that room, or is it a secret?

What is IN the room?

There is enough information given for you to give a fairly good guess