On the bank at the edge of the road where Frymans Lane meets Powdermill Lane (TQ80651934) there are a couple of quite distinctive spikes of the yellow flowers of fringed loosestrife (Lysimachia verticillaris) which grows as a native in north and east Turkey, Caucasia, Crimea and northern Iran. The identity has been confirmed by Hugh McAllister, an expert on this genus.
Quite where it has come from locally is difficult to suggest. It is certainly a garden escape, but this particular corner is not the best place for fly tipping garden waste. It apparently does not set viable seed in this country.
McAllister’s paper on this group of plants is here: http://archive.bsbi.org.uk/Wats22p279.pdf