Saw your query today. I visited Lanyon Quoit in September of 2005. Had trouble finding the right road, so stepped into a pub nearby, and before I could ask directions, an elderly gentleman pointed and said "Right up the road."
Should you wish to read about it, please go to the following page on my website:
http://www.saintsandstones.net/stones-lanyonquoit-journey.htm
There are additional sources on the page also.
Cheers,
Jeff
P.S.: Cornwall is beautiful!!!
Something is not right. This message is just to keep things from messing up down the road