fitting a gas fire in an existing fireplace

[oldsomeman]

I have a 1902 house with marble fireplaces, behind these are the original tiled grates.
At the moment they are covered over and gas fires placed at the front in etenite. However the fires need replacing.#I was wondering if I can fit gas fires inside the old grates and so open up the old tiled grates for display...although I realise that I might have to put new liners up the chimney.
Any ideas what other work might be involved if models i can use please?

 

[jazzcricket]

Your best bet is to go to a fireplace shop and get some advice, or alternatively get a gas safe engineer to have a look, they will know the regulations.