I think I'll be able to spot them now!This could be the 'too small to be a Comma' that I've been seeing for the last few days... and not been able to get close to because it zipz off before I get close enough.
UPDATE:And thank you Susan, yes.... it is the Violet Fritillary... one stopped long enough for me to take a good look. It knew I had the chainsaw in my hand and not a camera!!
What I was seeing was one like your third photo, with the very pale markings on the wing edge... they [it] were [was] always settling on the silvery old wood at the edge of the nursery area by the bief and some of those pale markings were blending with the colour of the wood.... giving a ragged, Comma-like edge.