It was good that you missed the thunderstorms. There was a long line working their way up the east of Scotland. I assume that the must have mostly passed to the east of the Cairngorms.
I have wild camped above 1400 metres before, but that was not the same as your camp, as it was in an Alpine valley and I could get a beer by walking a few km into a nearby village. However, the washing facilities consisted of a fast flowing glacial stream, which was freezing.