I really don't understand this:

I've done the 3 lower parts of this chain, now that I've mastered everything (except Artisan) I can't get the quest that gives me access to the superior workbench? It's really frustrating, either my account is bugged or there's something I'm missing.

My friends and various guides on the internet have told me you get the quest from an expert woodworker, so I tried one and all it does is trade me. I then tried to go to the woodworker guild, the original woman who gave me the other 3 quests and crafting masters; pretty much every NPC I can think of that would give me the next quest so I can carry on with my woodwork.

Can anybody shed some light on this matter?