There was some discussion about this on todays ride. I went over both twice today and the heights (as measured on the Garmin) were consistently Buriton 141 metres and Butser cutting 163 metres. Note this is heights shown after readings were corrected for pressure changes.
The seatpost on my Dawes Galaxy had been stuck for over 2 years. I couldn't move it and neither could the bike shop. At first I wasn't too bothered but when I was fitted for my new bike I realised that the saddle on the Galaxy was too low making it less comfortable and inefficient. I searched the web and methods of sorting it looked rather extreme and risked damaging the frame. Then a club-member suggested the Seatpost Man. He (John Lee) is based in Chorley, Lancs so not local but on the way to the North. He was very good at agreeing a time to suit me. I left the bike with him and in 2 hours it was done. Cost £60 but cheaper than a new frame and the bike is now a pleasure to ride (as well as being easier to pack up for touring!).
I'd definitely recommend him to anyone who has a similar problem. And what an excuse for a trip up North - cycling or otherwise!