So, I have a 52 Rogue who is in the area round Tuldio retreat, and have realised that whilst it seems to have all the npc's of the other cities, it is missing a Banker, Guild Banker, and Auctioneer. Otherwise, it's a fully functioning city. It has all trainers, and trades, but not the 3 above. Simply by adding the 3 above, there is effectively a 4th area to go to to craft in peace, access the AH, and banking.