I was in M&S today and they had reduced their cakes to a ridiculously cheap price....so I bought an extremely chocolatey birthday cake and a white chocolate and strawberry cake (both cakes with buttercream on). Has anyone successfully frozen one before? If so is it best frozen in slices or whole? - My friend tells me she freezes Costco birthday cake and it defrosts fine which is why I am considering it. - They won't be used for anything special just the kids etc