Hello Peter,
Unless your insistent on steel I would try aluminium; it's lighter, probably cheaper and requires much less maintenance. Also "aluminium carpenters" are much easier to find locally.
I would recommend either Brinas who advertise in the GAA, contact Jose or Cerrajeria Mateu in Altet opposite the tobacconist.
Jose at Brinas speaks good English but I've found their prices are getting a bit expensive, Mateu don't speak any English but with drawings, dimensions and the usual gesticulations you'll get there. Their prices are very good - they double glazed all my windows last year. Sometimes you're lucky to catch them open and they may shut for a good while in the summer.
Good luck
Dave
