Wetland/woodland plant for ID

[King Edward]

This is probably something straightforward, but I can't think what it is. It was growing in very wet ground with sedges at the woody edge of a marsh in Herefordshire. The leaves are somewhat hairy with short hairs, and the petiole has a deep channel along the upper surface. The rosette is growing at the end of a creeping stolon.

[Dorts]

Looks to me K.E. like a young plant of Marsh Valerian - Valeriana dioica, a species which has rooting-runners. As you know, the lower leaves are entire, the upper flowering shoots have pinate leaves.
Can't think of anything else it can be.
Dorts.

[King Edward]

Thank you, Dorts, that sounds a very plausible suggestion. I'll try to revisit the site again next summer, and see if I can see it in flower then.