It is done with command blocks, teleporting you to the islands from the main platform and back as the Custom NPC didn't spawn for us (Not sure why). It has a few simple rules that we're using for our map, but are suitable for most people.
Our Server owner James (Athion) and our admin team (Emoir, Jolli, Leonoor, Dries and myself), made it a little prettier by adding the central building and fences. This is where the command blocks on the islands go to. It also houses a few rules we have chosen to add.
Thanks for taking a look guys.
EDIT: I've been able to get permission from Paisley to redistribute our version of the map as well as received some information as to why we might have had issues. Thank you very much Paisley for that :)