i want to take out the ornimental fire grate at home and replace it with a lpg real flame fire, i have a unused brick chimney behind.

where best to buy something like this and what else do i need to think about ? can i just stick it in the whole and get a local fitter to check it ?

You may have to have the chimney lined with metal tube to protect brickwork from condensation. I think this would apply with a gas boiler.