I asked...... and John Dillinger gave me the answer I needed - spot on. Mine is a fan assisted electric oven. If yours is the same you pre-heat oven at 220. Then cook after preheated for 25mins on same temp. Mine were ready though after around 20mins.
You want to be careful. I read about this Swedish scientist who became infertile when he accidentally heated his chestnuts to 70 degrees with a laptop.
