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Not sure of the size difference between the two. This one was just over 1m tall when the photo was taken with leaves about 35cm long!!
Might be worth having a look at flowering time if you are going again. I'm very happy to be wrong - photos can be difficult
I am certain that this is sphondylium, as the leaves are nowhere near as 'toothed' as in mantegazzianum. Compare one I posted recently. The leaf shape is very different.
My Flickr photos...
Lat/Lng: 50.6466, -1.1883
OS grid ref: SZ574833