One would have to assume that the occasion portrayed was prior to Queen Victoria purchasing the Balmoral Estate, when she was considering the purchase of Ardverikie on the S.E. shore of Loch Laggan - filmset for "Monarch of the Glen" series.
In those days there were no estate roads along the S.E. shore of the loch. Access to Ardverikie Castle was by rowing boat across the loch. H.M. was said to have been very enamoured by her visit to Ardverikie, until the return boat-trip across the loch at eventide. The vicious nature of the Laggan midges scuppered the sale!