I've actually written a recent paper on the carvings at Bidston Hill, I don't mind sending it over if you'd like to read it.
Mark Olly is not someone I would regard as being reliable, albeit his intentions are good. He is more of a re-enactment historian, and so much of what he writes/produces on TV is not founded in archaeological or historical fact. I seem to recall him linking Birkenhead Priory to templar activity, based upon a few old tombstones (and not long after the Da Vinci code brought Templars to the forefront of people's minds!).
There is a massive amount of evidence we can point at to dismiss the carving as most likely being post-mediaeval graffitti - too much for me to type up in my lunch break!
The Belisama link is a case of pure speculation. If you look at the Ptolomy maps, the river concerned is more likely to be the Ribble than anything else. The 'solar boat' shaped Mersey was a series of pools during this time, and would certainly not resemble any shape that it does now. This argument was dismissed some time ago, I can send you a link to a Journal discussing it if you wish.
Thinking on, I've also read somewhere on this site about someone interested in rows of stones in Bidston. I've not seen them to be honest, but I have access to maps of the entire area of Bidston dating to 1665 if anyone thinks they may be of use.
Not sure if this works....but here's a scan I'm working with at the moment of Bidston Village in 1665, they formed part of a survey by a chap called Thomas Taylor who surveyed the Manor of Bidston after the Civil War. The reason for this lay in the fact that the Earl of Derby was a condemned Royalist (had his head chopped off!) and his lands were confiscated by Cromwell's new parliament. The survey was to provide some valuations of the land.
This scan only shows the main village centre, as that's what I've been working on mostly. However, I do have maps from era for all sorts of places, mostly in North Wirral.
That`s superb mate.Still legible in any case.If you have probs with posting maps,such as too big to post in 1 go then Mark can help you out.I sent him a map in 6-8 sections and he managed to stitch it together and post it as 1.
As long as no one is planning any metal detecting or digging, I'm happy to assist anyone in any archaeological/historical research in Wirral if they are interested. I'll make an effort to scan some of these older maps when I have time, and will PM them to anyone who's interested.