Is it for a real fire or just decorative? There are cheap options at the DIY sheds, ( I bought one for a non-functional fireplace in a place that is currently rented out ) but you would probably want something better quality for heavy use.
My current favourite is Hereford, by Jim Lawrence, though with a width of 80 cm it's too big for most of the fires here - nice for the main room though.
Are you sure that you want to put a wrought iron fireguard in front of that very ornate fireplace? No matter how simple it may be, wrought iron, by its nature, tends to be a series of decorative shapes, and I tend to feel that decorative shapes viewed through decorative shapes can become very busy and mutually detractive.