Travatine Mosaic Bathroom Floor - further info

Hi, can you give me an approx price (per sqm?) for laying variable size mosaic tiles on a 300mm mat to a 3 metre approx bathroom floor with pedestal basin and floor standing toilet? Is it much more work than laying 300mm ceramic floor tiles? If so what would be the expected difference in price? To be laid on 6mm hardiebacker board fixed directly to floorboards please Thanks