I needed 3 more 3 metre gravel boards from In-Excess and another Arris rail from Wickes, both cheap sources.
I'm not sure why but the process was much less simple this time and I made a few mistakes. But I managed to finish it just after sunset as it was getting gloomy and, with the help of my young neighbour, I got it into position.
Next time I go down I just need to dig in the 'arris rail' positioning pegs o fix it in position.
On the way out I came across the two parsnips I thought I had taken home last night! They were lying where I had left them after digging them out! It was a good thing we didn't have a frost last night!