Interesting reference: nice to credit the researcher, Amanda Maclean. Folk Music Journal, Vol 11, No 1.

However, Andrew Lambie, or Lamb, of Edinburgh, was 'one of Her Majesty's trumpeters'. He also appears in the records of the Royal Life Guards. In 1684 he was described as trumpeter to a first cousin once removed to the Laird of Fyvie. Apparently he played trumpet at the funeral of the Duchess of Wemys.

It may be that this person was in the mind of whoever wrote the ballad. But there is no evidence that he was actually at Fyvie or that he was accused of witchcraft.

Whether the events described in the ballad ever happened is another thing, something that will never be proved.

But for me, none of this proves that the ballad demonstrates insider knowledge such that it must have been written by a member of the lower orders rather than somebody from another social sphere or, indeed, a ballad writer with some local knowledge. And this what the example was intended to prove.

The castle has reasonable reviews on TripAdvisor.