Should have mentioned a few other things...
I'm on Windows 8.1 x64
I've tried fiddling with settings in my router and the adapter. It will connect to the 5ghz band when that band is enabled in mixed mode OR 802.11a mode. Again, I think this all relates to the adapter settings which offer every option (a/b/g) EXCEPT n.
I've tried uninstalling/reinstalling drivers