I had a hunch that it was time for Damselflies and, sure enough, I found a single male of the Large Red Damselfly - Pyrrhosoma nymphula. Wonderful colour.
It allowed me to take many close shots, so I assumed it had freshly emerged.
The Blues won't be far behind.
I didn't even look at the fern, but it looks to be Scaly (Golden) Male Fern.