Thanks all. Our fireplace is a little unusual in that it is very large and raised from the ground. Effectively normal fire surrounds won't work. I want to fit a glass ( fire ) door to the front which is a special type of glass. I am told that it does get hot but not hot enough to be dangerous. Hot enough that if the toddler touches it, she'll go 'ouch', but not hot enough to harm. If it's too hot, I'll put a fire surround around the glass too- at least I'll know the worst she can do is a slight burn, and not seriously injure herself, the baby or burn the house down!
I can't see the doors I want in that link Dr.M- those are 'real' Stanley cooker doors, which I don't think would suit, as well as being much too small, but thanks. I did google but all I came up with were similar links.