There were hazelnut shells in the fire at that mesolithic house up by Howick. Lots of them I think.
Given that the shells were deposited in piles during the mesolithic, and seem to last for a long time, part of me wonders if early transhumanant peoples may have found the evidence of their ancestors hazelnut feasts, and used this as clues to the suitability of the site for a camp/settlement. No way to ever prove/disprove that one, so it goes on the pile of random daft theories, catalogued as 'Half-baked idea No. 14340'