Can I Get A Gas/Electric Fire Removed Safely And Sell It?

This needs to be electrically isolated by a competent person pref.enrolled with NICEIC, ECA OR ELECSA. The gas connection need to be terminated and capped off by a gas safe engineer. You might need services of a builder, who can remove the fire place and patch up any decorative works required.

Electrical works need to be performed by a Competent Person - as this falls under Minor Electrical Works, he/she does not have to be registered with a scheme such as NICEIC/STROMA/ELECSA/NAPIT etc, but it is preferred for peace of mind. Therefore, if your gas engineer is competent in electrics, he will likely be able to perform this simple job for you. However, from a gas point of view, gas works must be carried out by a Gas Safe (previously Corgi) gas engineer. As for selling the fire, both an electrician and a gas engineer will be able to give you an idea of safety of the appliance, but ultimately, you are allowed to sell anything you like, so long as you are honest and give a full and detailed description of the item (ie: untested, if that is the case). I personally feel that a buyer should seek advice from an installer before buying.