did you ever look over the walls and in the hedges, close to wherever the van was broken in to?
sounds a longshot i know but...
three times i got stuff back when police and i searched close to where my car had been parked.
sometimes you get broken into by thieves who have seen or know of something inside and they
only take that, others if you are unlucky just smash and grab anything that is there as quickly as
possible, then round the corner and out of site of vehicle, check what they have and dump anything
that is of little perceived value to them and keep the rest.
thats why you tend to find the bag/briefcase with all the paperwork or sentimental stuff thrown over
the wall but they have kept the cash or jewellery etc.
anyway just a thought, but if you are desperate to locate it, it may be worth a try.....