I spent a long time looking in all the wrong places before I finally… swung around… to the right way of thinking. Brilliant hiding place, FP awarded.
I’d figured that this path, being listed as a bridleway, would be suitable for my bike: i.e. relatively broad and flat, no stiles, etc. I was partially right, and the path soon became a little bumpy for my mostly road-going bike, but it worked out.