I visited the Bolitho School in Penzance, today, and near the entrance to
the main drive is a Holm Oak with mines from 2007. Which seem to be
Acrocercops brongniardella.

http://www.leafmines.co.uk/html/Lepidoptera/A.brongniardella2.htm

The silver gallery can be seen, as can the remains of the papery blotch.
Only problem is I know of only one other record for Cornwall recorded in the
Victoria County History at Millook. Is anyone aware of any other Cornish
records. If not I need to pass on the mine to someone else for
confirmation.

All the best,

John