Carleenimlach your fireplace is stunning. It is infact original in bungalow detailing, and the bricks are not painted. I know this treatment very well. They had a brick stain applied, which is a red oxide painted to give the appearance of an even red brick face, this was done when tuck pointing is applied to the mortar course. I can see yours was.
It looks as though it was charcoal, also another Edwardian bungalow detail, and the lines accentuate the archway. The mantel itself is absolutely beautiful.
I myself would restore the brickwork, and let this period detail return to being the heart of the home. The hearth bricks definitely need to go, in their place I would lay a single slab on stone, which is a little costly, but overall, is worth the expensive you save in defacing the brickwork anyway. I suggest a rough sawn bluestone slab that will further enhance the charcoal tuck pointing, and grey is not only a current interior colour, but it is also what edwardian bungalows often featured. So you get to have a current, updated interior whilst preserving the beauty and character of a period home.
This is where the homes value lies.