D'you know what, I saw something this morning I've never seen before, and I've been around for very long time.
Un-Izzielike, I didn't have a camera handy, which I very much regretted because looking up at the sky, the cloud formation was very dramatic, like a "mackerel sky", but much lower. The cloud billows were so big that there was only room for about four of them across the whole of the visible bit of sky (I live in suburbia, horizon not often available).
There were about four big straight bands right across the sky, with duck-egg blue clear sky between. The whole effect was stunning.
Something like this, but not like this. Much lower, much bigger.