The Spitfire came before the F16 or while the F16 concept was in its infancy I think, as a dedicated two-up boat. It is built in England at the White facility and is mainly a boat sailed around GB. At least that is my impression. Looks like good boats with high quality racing and some great fun. Their "Spituba" and "What did you do in the weekend" videos are classics.

Ref: http://www.spitfiresailing.org.uk/