Martin, could possibly be a Silence Twister, which is a lookalike Spit designed for aerobatics, powered by a four cylinder opposed 2.6 litre , 107hp engine. Saw the 'Twister duo' do a magnificent evening/ night display at Bournemouth with pyrotechnics and lights a couple of years ago, really good!
Designed initially as a r/c model, then scaled up to full size, bit contrary as we tend to do things the other way round.
One of the pilots then was Guy Westgate who previously gave one of the best displays I have seen, at Shoreham, flying a glider, to a music track, with smoke generators on the wing tips, in a beautiful clear blue sky, really pushing the aerobatic envelope doing manoeuvres I had never seen a glider do before. Really really enjoyed that.
Adrian.