An evening on Viewranger suggested that it would be a 22km route with around 500m of ascent. I've made the route available to download here. The woods aren't on much of a hill but to cover every path needs the small undulations to be addressed numerous times.
As I'm still getting back into the swing of long runs I hoped to take it steady at around 8min/km but in the end the overall pace was slower than 9min/km.
Here it is done, it took over 3 hours and in my current state of unfitness it was quite hard going. I saw some dog walkers quite a few times and felt I needed to apologise to one for popping up so often.
That's my weekend running basically completed now, just a few easy km to achieve the week's target.