Crown Bronzing Kit

I've just painted this room and I'm thinking of painting over this fireplace on which I had applied (quite a few years ago) a product once known as 'Crown Bronzing Kit'.

I can't say whether I still like the bronzing or not but, if I decided to paint over it, what preparation would I need to do?

If you have alternative suggestions on the fireplace finish, I'd be eternally grateful. Also, I'm thinking of painting a graphic on the piece of MDF - if you have any wise words on that - I'd be thankful too.