Despite repeated visits 1-5 Jun, no sign of any northern damselflies at the pond near Loch Garten. No sign of northern emerald at Uath Lochan nor (per a friend) at Loch Maree on 4 Jun. Late spring put paid to chances of both, I guess.
I hesitate to say this, but BDS website now has a report of northern damsel at Loch Garten on 9 June. Also allegations of "hot weather".