I can't actually find this post anywhere on the site, only via a search engine, but I hope you are able to view my reply as it may be of interest to you. It is the general (but disputed) beleif of some local residents of the Malvern, Eastnor, Ledbury area that an ancient, hollow oak tree that stands on the north edge of an amphitheatre of earth and rock marks the centre of the laylines. The tree can be found in a field on the lower western slopes of Ragged Stone Hill, just off a footpath between Hollybush and White Leaved Oak. I've actually writtain an article on "The Magic Oak" on my weblog http://moelbryn-eastnor.blogspot.com