Front Lounge Part 2

Today, with some help (thank you Ted!), the rest of the floorboards came out. Then we decided to get rid of the non-existant-fireplace-hearth. As it turned out, it was a block of polystyrene, covered in a 10mm thick layer of pretend-marble composite. Unfortunately underneath it is the most had concrete block on the planet. We've tried bashing it (need it flat so that we can put floorboards across where the hearth used to be); but it wont budge - looks like we may have to go and procure a jack-hammer of some sort...