Thanks for your input mate, I appreciate all the advise and input I can get. I only say this because when I have been at the PO sometimes I have seen drivers collecting parcels and have seen them scanning them. But you may be right, it still seems more likely that it would be the drivers then given that they disappear between the PO and the sorting centres. 

On the liquid leaking, AP have a policy that highlights these things and this is documented if this happens. Also it is very rare for my items and in sending approximately 3000 bottles I have NEVER had a smashed bottle because I pack ridiculously well and use very strong double walled boxes. However, I have received smashed bottles to me. As I say at around 3000 bottles sent not one customer has ever said that their bottle leaked or smashed so it is very rare for my business at least so I don't believe 4/4 or even 2/4 could occur because all my bottles are sent with copious amounts of bubble wrap, double walled boxes and either packing peanuts and more cardboard protection. I honestly believe I could drop one of my parcels from a 2 story building and it would survive.