Another thing I might consider doing - given the fairly high-value item that was initially delivered, and certainly if any more high-value items are delivered - is to inform JD Williams that no responsibility can be taken for the secure storage of high-value items fraudulently purchased and/or delivered in error to your address. You might also forward to them copies of the correspondence (if any, and suitably redacted of course) between you, the police and your bank so they know this isn't just someone panicing about a mis-delivered pair of socks.
If your home insurance company offers one of those 'free legal helplines' you might want to consider contacting them in order to clarify how insurance matters stand if multiple high-value items which are not yours are present in your home without your 'permission' as it were ...
I would also go round to all my neighbours and ask them to refuse to accept any deliveries on my behalf, no matter what the delivery person says, and leave a clear notice on my door to the effect that deliveries must NOT be left outside, or with any neighbours, under any circumstances. Of course that wouldn't actually stop someone leaving something outside the door or pushing something small and expensive through the letterbox, but it might limit deliveries somewhat ...