it is a tree that has an open habit so the frame work is quite good. You can prune it to the lower leaf buds and see if it grows in the shape you would like it to.

Thanks - I wonder if the soil is wrong though for it to be so sparse as others say it should grow by feet each season?

Whether the soil is chalky or not is irrelevant, they're not fussy about that, and as there's a tree behind it I assume the depth of soil is sufficient. However I do note a tree trunk behind the plant, and they seem to be fairly close together, so that the roots of the tree behind will be dominant and may deter the roots of your new elder. Do as Seaburngirl advises, but also, I would scrape away the shale layer you have at the base, rake in some Growmore around the base of the plant and keep it watered as necessary till it gets going properly.

Many thanks for all that!