That's some kind of dock (Rumex), perhaps common yellow dock. An important
medicinal in its own right, but not comfrey. Comfrey is not common in the wild in most places, and the leaves are coarsely downy, a bit like a squash leaf only finer. They are shaped sort of like the dock leaves and the plant does have a similar habit. Flowers are different though......You can probably google an image or two of it so as to have it in mind.....