Then the weather happened and I realised that I needed to find a way of pitching the tarp in a more weatherproof way than the lean-to stylee that is my preferred way of putting the tarp up. A flying vee would work but there wasn't any guarantee that there'd be a tree and space to pitch the tarp in the desired position to shed the wind/rain. As my tarp came from BPL I took a look and there was one pitched in the cave or pyramid stylee; using two trekking poles, the tarp has three edges to the ground - ideal.
So I set to and put the tarp up in day light, then in several shades of dusk and twilight, and finally in the dark with the aid of a head torch. It was quite blustery on Saturday morning so I pitched it again to see how it stood up and to checkout the living space.
This is a very stable configuration and I expect it to keep the weather off. I could sleep with my feet towards the opening as there's enough clearance at the closed end for my head. I can sit up under the tarp at the open end and cook with the Bush Buddy, and there's enough room should a visitor wish to call. Roll on Friday evening :)