Thanks, although it seems I have another problem. I decided I was going to use the heavy armour from L0rd0fWar's Mercenary Pack however for some reason why I put the armour in the inventory of the NPC, the NPC does equip the armour at all and is just nude. I tried setting it as a default outfit and as part of a leveledlist and still the same issue.
I got a bit suspicious about the issue when in the CK the preview of the NPC didn't update either when adding the armour and still shows as nude.
Edit: Nevermind, turns out I had used the wrong keyword and that was messing up the whole leveledlist preventing it from properly spawning the armour. Other than that little hiccup the Leveledlist Solution works perfectly so thanks for the suggestion @Havoc. Although I don't suppose if you know how to make sure a specific armour material spawns like Shadowed?