Warbird Flights
Dependent on the weather and light there is a company which offers flights in a helo acompanied by either a Spit or by a Spit and Hurricane which formate round the helo. This has not been running for very long but is proving very popular especially for air to air photography as you don't get many chances like that! They do most of their trips in the area of the White Cliffs so it might be possibly them.