Stoat's Nest

An unidentified Billinton B4 heading the Brighton Pullman Ltd train in what is probably Bronze green/ red oxide roof and ornate gilded livery with open verandah Pullman cars. It has 7 full length cars and a Pup at the front. The head code on the buffer beam indicates its route is via the Quarry Line, opened in 1900.  I thought at first it was the Southern Belle, having 7 cars, but the Southern Belle didn't begin until November 1908  and its livery was Cream and Umber with white roofs, vestibules instead of open verandahs and ran on 6 wheel bogies, not 4.  A B4 was unlikely to still be in Stroudley IEG that late.  My Inspector Clouseau side came to the conclusion that the photo must have been taken sometime between summer 1900 and late summer 1908 somewhere between Norbury and Haywards Heath.  Can anyone hazard a guess at the name of this service and whether it ran from Victoria or London Bridge.