There's a place almost opposite the Goksular Yapi Market (known as B&Q by most expats) with a big display of wrought iron furniture. They make it all at their forge at Gunlukbasi. They also make, supply and fit gates from there too. I can't remember the name of the shop but the lad that runs it is called Ramazan (also known as Ramos) and he speaks excellent English.
There is also one on the road out of Fethiye near the traffic lights at the base of the hill leading to Ovacik (on right hand side). Very reasonable, doesn't speak english, but will call someone to translate. Very little shop with a few bits of iron furniture outside. He has made gates etc for us.
We've found in the past with that one that they have very different prices for Turks and Yabancis. We caught him out by sending a Turkish friend in for a quote and then going in there the following week ourselves with same specs. His price to us was over 3 times that which he quoted our friend.