Which locks?

[Handystevey]

Hi all, having got my van, bit shocked at the ease of breaking into it is. I know I'm going to have to fit new hykee lock but in members views are the std deadlocks ok or is it worth paying the xtra £100 quid or so for Armourshell locks fitted at the tops of the nsl /rear doors and what is this thing about the OBD and is it worth putting extra locks on both front doors too? Please bear in mind I wasn't expecting to shell out loads of money when I bought the van..Thanks in advance...