The BoB was all about the defence of Southern England, not the far north of Scotland, well not directly at the time anyway.
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Pete, Not wishing to have a go, or sound nationalistic ( though I am proud to be Scottish) but I always thought Battle of Britain day was as more about commemorating and remembering those who flew, defended the airfields and worked all hours to keep the aircraft servicable.

I would imagine that there were a substantial number of Scots involved in this and, as such think that Leuchars, and Scotland, has every right to stage a Battle of Britain airshow.