I've just had another kitten showing Champagne (pot luck as i forgot to seperate the boys and girls after their last breeding session), this from Chrissy, a starter who hides ASH Cream & White, and Aahan, the father from the previous pedigree with Jane (above).
This should show that Tonk - Champagne is dominant to Cream & White. Aahan has passed his shown (or possibly hidden if he is pure Champagne) and Chrissy must have passed her hidden Cream & White Tabby.
This shows Cream & White as Chrissy's hidden from a pairing with a Siamese - Flame as Cream & White is dominant to Flame, therefore it cannot come from John so must be from Chrissy.
Abi.