Growing in a gravelly paddock
No interactions present.
It seemed to key out as this but I wasn't too confident about it!
Tripleurospermum inodorum is not easy to distinguish from Matricaria recutita (aka Matricaria chamonilla). By eye I would have identified this as the former, based on the flat disc of the capitulum, but I am not 100% accurate at distinguishing them by eye.
In the field the two species can be distinguished by floral scent (rub your finger on the disc and then sniff your finger) - usually aromatic in Matricaria recutita, and absent or weakly sweet smelling in Tripleurospermum inodorum; and by the nature of the receptacle - more or less solid in Tripleurospermum, and obviously hollow in Matricaria.
Other similar plants are Chamaemelum nobile (prostrate habit), Tripleurospermum maritimum (succulent leaves, coastal habitats) and Anthemis sp. (aromatic foliage).
I initially thought it could be C.nobile but then discovered this hasn't been recorded in the BRERC region since 1896 (?) Didn't detect any scent suggesting T.inodorum and receptacle seemed quite domed (not obvious in photo) but wasn't sure about the "hollow" feature (do I need to dissect the flower?).
... cut the flower in half (a fingernail will do the trick) or rub off the flowers between thumb and forefinger (I'm not sure that it will work for young flowers).
... Chamaemelum (and Anthemis) from Tripleurospermum and Matricaria is the presence of receptacular scales (i.e. you would need to dissect the capitulum) in the former, and their absence in the latter.
Unlike Poland, Stace doesn't mention that the foliage of Chamaemelum and Anthemis is strongly aromatic, which would seem an easier way of distinguishing them from Tripleurospermum and Matricaria.
Lat/Lng: 51.41389, -2.47435
OS grid ref: ST671684