Thank you to Andrew Boe, who has dropped me line explaining something that I have not noticed before:
“Leaves at the bottom of a tree are often larger on the shadier North side to make the most of available light. This is often the case in Sycamore. They will also be darker due to the high concentrations of chlorophyll.”
From now on, I’ll be on the lookout for these shady characters. Sorry, couldn’t resist.
Andrew has a bushcraft blog which is well worth checking out here.