23 Dec : a Horrible day, entirely my fault, although the nice thing is that the sun shone all day and made the work warmer. I wish I had been more precise about measuring the centre of the group of panels, I just worked from the centre-pipe which I thought was central. But it shows yet again how important accuracy is. The left hand array should have been 2 cm to the right, and the right array would have been better if it had been 4cm to the right. In each of the arrays, the pair would have been better a centimetre closer to each other. Seems small, but matters a lot when trying to fix all those bulky 40mm pipe fittings and stiff rubber hosing, with all the jubilee clips required.
I was close to taking the whole lot off and drilling yet more holes in the rails, to refix them.... but thankfully, there was enough 'give' in the fixings to move them sideways, enough to fix the stiff rubber hosing. By now it was dark, and I hope all those Jubilee clips work well! They certainly make it easier to fix the hoses!
Later in the evening, back down at ground level in the conservatory, I fastened aluminium angles to the Polycarbonate front panels (large!) using pan headed screws... this all went well, although its difficult to handle such large panels on my own.