If you are considering walking this route yourself, please see my disclaimer. You may also like to see these notes about the maps and GPX files.
Shortly after the fields to my left ended, I left the drive and took a footpath on the left. This ran through an area of grass and bushes at the foot of Pyrton Hill. After going through an open gate and entering Shirburn Wood, the footpath almost immediately forked left from the faint track it had been following, and ran along just inside the edge of the wood, with fields to my left. The path soon turned right and then left again, still just staying inside the wood.
The path going northeast back to Shirburn Hill
The path going northeast back to Shirburn Hill, now running along the edge of Shirburn Wood
The path going northeast back to Shirburn Hill, just before it turns right
The path going northeast back to Shirburn Hill, after it turns right
The path going northeast back to Shirburn Hill, after it turns left
I could now see Shirburn Hill ahead of me. About a third of a mile after turning left, the path left Shirburn Wood and started a long climb up Shirburn Hill. Near the top of the slope the path passed through another bit of Shirburn Wood, then I went over a stile on the left and crossed an almost flat pasture (aiming for the far left corner). I then just had to cross a road, go a few yards left and take a short path that led into the end of the Cowleaze Wood car park.
The path going northeast back to Shirburn Hill
The path going northeast back to Shirburn Hill
The path up Shirburn Hill
View back from the path up Shirburn Hill
View back from the path up Shirburn Hill
The path up Shirburn Hill
The field before the road that passes Cowleaze Wood
I was disappointed afterwards to work out that the walk had taken me 4 hours (excluding the extra bit caused by leaving my map case behind!), the same as it had in 2022. Back then, I'd not quite recovered from the mild "long covid" I'd suffered, and I distinctly remember being slowed to a plod from where the Ridgeway passed the foot of Shirburn Hill onwards, but this time I felt I was still walking strongly when I got back to my car. I've checked the timing by looking at the timestamps on the photos I took then (I actually took 20 more photos in 2022 than this time). And as some of the route was new to me in 2022, I would have spent a bit more time checking my map. So I'm bemused by the fact that I didn't walk the route a little quicker this time - I can only conclude that I'm even less fit than I thought I was!
I certainly enjoyed the walked today, and I'd be happy to do it again.