Trawling back through recent photos I found this one that I took at Scarborough in May. I took it because the rippled edge of cloud looked interesting. After my research into the wave clouds in Scotland, I now think that these are probably going to be Kelvin-Helmholtz clouds, but not as good as the best examples.
https://en.wikipedia.org/wiki/Kelvin%E2%80%93Helmholtz_instability
