The band is pretty much the same in both bras. The 36FF bra has bigger cups.
Freya bras 36F - 17 products
80F - Chantelle » Révèle Moi Perfect Fit Underwire Bra (1571)
Gossard Shimmer Lace Padded Push, Up Bra with Lace Back
Freya » Deco Moulded Plunge Bra (4234)
Comparing a Freya Deco Moulded Plunge Bra (4234) with Freya Deco Moulded Strapless Bra (4233) in 28G
Freya's favourite Deco lingerie collection in Black features the must-have Moulded Plunge Bra, offering stylish functionality for a flawless shape and
Deco Black Moulded Plunge Bra from Freya
34F - Cleo » Marcie Balconnet Bra (6831)
Comparing a 36FF with 36F in Freya Deco Moulded Plunge Bra (4234)
Freya T-Shirt Bras
Cleo » Neve Plunge T-shirt Bra (7196)
Moulded Shapes Explained
Freya deco moulded plunge bra
Types of Bra & Bra Style Guide