Yet another in the motorway series that line the M1. It's sister caches have proved popular and this is yet another easy park and grab. No reason to do this one at all unless you really want another smiley.
There is a slight wrinkle with this one. If you are travelling South you can't exit here. You will either have to exit at 12 and back track through Dunleer or exit at 14 and travel down the old road.
Similarly if you are travelling North you can exit at 13 but you can't rejoin the motorway North at this junction. Again your options are either 12 or 14 to continue on your travels.