I wonder what Dowding and Park would think? Would they call the Mk 26 a Spitfire when it is sporting a VNE of 220 knots, a ceiling of 18,000ft and a chevrolet engine? Not sure if it would do so well against old Herman's Bf109 boys over Kent.
While Mrs Grace's comments may be a little harsh, I think her general point is quite correct. It's cheeky at best to take the name Supermarine Spitfire and assign a Mark number to a scale replica, even if it is legal, honest decent etc.
Still, that said it's a lovely replica - not perfect in the lines, but still lovely. Best of luck to the boys building up the squadron of them.