It won't be a Saab. On the BA Cityflyer thread it's off to Rotterdam for the summer. BA won't be basing anything here in the near future. Shame
It might not be BACF who end up operating the 3 x daily service. The BLL based BA franchise operator Sun Air of Scandinavia has been looking to add new routes from LCY.
Sun-Air operate a fleet of 32 seat Dornier 328 aircraft. Personally I think this would be the perfect aircraft from the IOM-LCY Route.