I think this is a Polypodium (polypody), but it might be one of the Dryopteris types.
No interactions present.
A Polypody as you say, unfortunately the only way to tell the three (at the moment) species apart is to examine the sporangia under a microscope!! It is possible to allocate "typical" specimens to species with a degree of confidence, but even then the error rate is reportedly rather high. I reckon I get about 40-50% right! Best to put it down as Polypodium agg unless you're going for the full microscopy.
BSBI VC Recorder
Okay, I'll change it to "agg". It was taken a month ago.
Have you got any photo's that show the whole frond from above as the shape can give a bit of a clue to which Polypodium species?
The frond at the top of the picture definitely doesn't look like P. vulgare.
This link shows all three Polypody's:
Alas, it was taken a month ago, while I was lost and before I knew that I was going to be submitting it here, and I'm not sure I can find it again.
Lat/Lng: 51.3, -0.9
OS grid ref: SU8266