Hi, I know it’s a long time ago now this conversation but the first one looks like an Ancylotropaeum. Tropaeum occurs in what is known as the lower crioceras bed which is member VI of a formation known as the Ferruginous sands, however in the VIII member called the upper crioceras beds you get something known as Ancylotropaeum which falls from the top of the undercliff and onto the beach like a conveyer belt, generally with these they are fractured in that way unlike typical Tropaeums. Nice find.
Fossilmeister: the first one appears to be a good section of Australiceras gigas from the Scaphites bed, it is missing the hook on the end but it is certainly not very common to find one with a decent center so great find!
the second one is either Deshayesites grandis of Dufrenoya transitoria it is hard to tell without a view of the venter.
as for the third one I have never seen an ammonite like that from the lower greensand are you sure it is from whale chine area?
Finally the last one from the grey chalk at Sandown appears to be either Acanthoceras juxesbrownei (more likely) or Acanthoceras rhotomagense but it’s hard to tell without a view of the venter. Very nice finds 🙂