Basically the radio that came with the van wont let you enter the security code to unlock it so im replacing it with a panasonic radio that was given to me.

From what I can see from pure visuals I'm guessing that I would need an ISO to 16 pin harness?

I can't post links but I've attached pictures of the connections and also a picture of a wiring harness on halfords that is advertised for kenwood.

I'm just wondering if that would be any good? I don't have any diagrams for the radio nor the van.

The connection on the back of the Pioneer will need a proprietary connection I suspect, and I very much doubt that the Kenwood one would be compatible unless - by some miracle - the pins are exactly the same! Have you tried searching on ebay for the model number of the Pioneer radio? You might get lucky!

Edit: Having just looked at the pictures, that Kenwood one won't even fit, the end pins are completely differently positioned.

Edit 2 - This one might work

Wow, just realised I was looking up pioneer and you said Panasonic, what a plank. Try this one - Look at this on eBay http://www.ebay.co.uk/itm/280594360996