This is my first post here and I'm getting an error message about the length of the post. So I've broken it into two parts. Sorry for doing that, but it seems I have to. I've written at some length to give a proper response to points other people have made.
I first tried dowsing using L-rods at Avebury, with no success at all. My girlfriend was with me, and she had some definite success around the Cove. (Success at what? is something I'll come back to in a moment.) She walked the same line with the same results, and then tried some other locations which also yielded results.
Two days later we tried the rods at the thorn at Glastonbury. She found something again, and to my surprise so did I. We both found the same results.
From then on dowsing with rods has always worked for me, so I'd encourage anyone who doesn't find success to go back to it and see if it's started happening.
Subsequently I carried out some quite meticulous work at several locations, printing maps and making on-site drawings. I was able to verify my findings on different locations, as well as verifying the findings of other people. On one memorable occasion I dowsed around White Horse Hill and verified many of Guy Underwood's findings, though without his level of skill and accuracy.
One of the most interesting occasions occurred in the grounds of Glastonbury Abbey. I'd previously traced a meandering line that I haven't seen mentioned in any of the books on the site. After meandering for soem distance it turns and enters the Abbey ruins through a wall at an angle sideways and downward, and can be followed and picked up on the other side of the wall by entering through a doorway.
As I was dowsing not far from that location I met a girl who'd been staying in the same guesthouse the night before. She asked if she could have a go with the rods, and I advised her to walk in a straight line until something happened. I kept behind her at a slight distance to avoid influencing her as far as possible. She picked up the meandering line, and I was interested to find that she expected it to head for a nearby church tower, which it moved towards for a short distance. She evidently expected the straight lines hypothesised and claimed by some writers on the subject.
Of course the line took her in a different direction, and I kept well back and watched as she followed the same course I'd followed months before, and traced the line through the wall at an angle. It was only when she'd done that that I came up to her again, and told her I'd traced the same line before.
The possibility of that happening by chance is basically nil, obviously, and the likelihood that I'd influenced her course is very low.
(See next post for what I think the signals are, and aren't.)