I bought a map of the Orkney Islands at the Loon Mountain Highland Games in New Hampshire, USA from a book seller (not too expensive if I remember). The map is part of he National Map Series by John Bartholomew & Sons Ltd., Duncan Street, Edinhburgh, EH9 1TA Scotland.. It is Sheet 61. It is a modern map. For older maps haunt second-hand book stores. I have bought one book on ancient maps. However, if I recall the Orkney Islands and Scotland were not too good.