That's it, that's the one I saw. It's finally loaded. It looks to me like it's dropping into a cutting but yes, without the lines either side, faded or missing it suggests an embankment too. It's just over the boundary and today, it looks like a house might be on that site now. Does anybody fancy sticking their head into the bushes beside the house to have a look?
If you look at the old Street View pictures on Google Maps, there's one where the vegetation alongside Oxford Road has been hacked right back. That reveals two gate posts, and what could be a gate, just where I reckon that track would come out. It's roughly halfway between the boundary line and the drive into what was than a bungalow miles back from the road (and has since, with its neighbour, been replaced by a small suburb).
You can't see any further than the rising ground immediately next to the fence, so it may or may not dip down behind that. But nothing on the maps, nor Google Earth's terrain heights, suggests it does - apart from that "subway" label!
