letterboxes v grid references

Hi,
new to the forum, hoping you may be able to help.
Having some trouble with local letterboxes. One on Bullaven hill was not on it's grid reference?
Another on Tor rocks, where I have found three only they don't correspond to the clues in that the name and the stamp are not related, one I found an older stamp did not have a clue in the book, another I found whilst in the right vicinity did not correlate with what I thought may be on the stamp.
So my questions are:
The names of the box are they generally unrelated to the stamp?
Are there many boxes with no clues in the book?
Are there still boxes out with clues in older books?
When the grid references are out by a long way, does one assume the box is different or moved?
Sorry this is so long!

Hi clickowls and welcome to the forum. I've only recently started Letterboxing so the answers below are my opinion:

The names of the box are they generally unrelated to the stamp?

Not generally unrelated but I have come across a few that are unrelated.

Are there many boxes with no clues in the book?

Yes.

Are there still boxes out with clues in older books?

This is a possibility.

Hope this helps.