Stinking Fleabane

Stinking Fleabane

Observation - Stinking Fleabane - UK and Ireland. Description: I just cannot place this plant. There were many specimens - perhaps up to one hundred - but all in t

I just cannot place this plant. There were many specimens - perhaps up to one hundred - but all in this small spot only, which was in the middle of a well-trodden footpath. Chobham Common is a NNR and a well-known lowland acid heath. At this particular point, the footpath looks to be of the type that is seasonally wet in winter and dries out in summer - the sort of place where you might find Marsh Cudweed, Water-pepper and so on. However, it is also very close to the M3, which passes above about 25 to 50 metres ahead, so there's a possibility that the plant is alien to the heath.
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I thought of groundsels and the alien fleabanes but it just doesn't fit my idea of any of them. As you can see, there are three-lobed yellow ray florets but the most striking feature is how glandular-hairy the whole plant is - sepals, bracts, leaves, stems. And the leaves are not groundsel-like at all but long and strap-shaped (all of them, from top to bottom of the plant), much more like those tricky alien Erigeron spcies, but, as far as I know, none of those have yellow florets or are so very glandular.
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I keep thinking I must be overlooking something obvious but I remain flummoxed and would really appreciate any help or suggestions. Thank you!
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Obsveration title UPDATED 29 Aug 2022 - with many thanks to lavateraguy for the ID