Ignoring the line from the east for now - further progress...
It is a while since I updated where we were with this so I will try and recall. . If we look at map 6 we know that the pipeline crosses the Hemel to St Albans road (A4147). Where does it go from here? Map 7 gives us our choices.
map 7
We have the choice of the nw-se Hemel to Bedmond road, or the sw-ne Bedmond to M1 (then Potters Crouch road). Sensibly I drove towards Bedmond first, via Pimlico, and what should I find just before Pimlico - but, yes, our friend the pipelines again. (you must be leaping out of your chairs with ecstasy - oh yes, I can tell).
pic 12 - bingo - there is our friend again. Note the pipeline indicators both showing away from Buncefield.
pic 12a - on the other (western) side of the road - the posts themselves are a bit overexposed, so fortunately I took a close up. (pic 12b)
pic 12b - close up.
Pimlico was a funny old place. It was a fairly damp September Sunday morning and it must be odd to have this bloke randomly walking up and down your pavements taking pictures of pipeline markers. I thought I would poke around behind the markers in pic 12 as there were a load of small bushes then a few trees and a view of the fields beyond. I went as far as the barbed wire fence and had a peer but couldn't see anything that would indicate a pipeline. I managed to take pic 13 quickly, because at that point I could hear voices. No, it wasn't the madness catching up with me but a couple of gents out on a Sunday morning stroll. I poked my head out of the undergrowth and they stopped talking. What should I do - stay where I was and just stand there in the bushes as they passed? Or nip out of the bushes in front of them? I did the latter, God only knows what they must have thought I was doing in the bushes. At best they thought I nipped in there for a piss. When I did walk out in front of them I was about 8 feet in front of them, and they remained silent for the next 100 yards as I walked in front of them, maintaining the 8ft gap, but shuffling nervously. I crossed the road to where my car was and their conversation resumed immediately.
Anyway pic 13 & 13a shows the hurried pics I took...
pic13
pic 13a
So, I have marked the point where the pipeline crosses the road in Pimlico on map 8. I went back and walked on the footpaths shown on the map, and, despite some lovely views there was no evidence of the pipeline, apart from a couple of possible gaps in hedges.
Despite (or perhaps because of) my embarrassing experience a few moments earlier, I had another look on the map to see which public footpaths would cross the pipeline, again just to see if there was any evidence other than than when the pipeline crosses the road.
map 8
There is a footpath (and it is much more visible on the 1:25 000 scale) that runs se-nw through Highwood Hall Farm. Initially it crosses a nice little field at an angle, then you go over a style in to the drive of the farmhouse, and if you didn't feel conspicuous already you do now. The footpath is poorly marked from here and you guess left. I went up the drive for about 50 yards and then the footpath turns a corner and you run into a small courtyard and the path stops. There is a little stile but it crosses a bit of hardboard which is too high to clamber across. I peered over and the footpath goes across a stables. There is a caravan there which was clearly occupied. A young woman led a pony with a child on its back across the yard in front of the stables, watched by a small gathering of other women. Somewhere around here a pipeline with the fuel that goes into Heathrow's and Gatwick's aeroplanes runs. I couldn't see any evidence of it and I don't think that the lives of the horsey people would have been enhanced by me attempting to clamber over the hardboard and then presenting myself in the stables. Discretion was indeed the better part of valour. I had every right to walk across the yard but would have felt even odder than I already did in doing so.