I have an Ideal Standard basin in my bathroom which I need to replace. Yesterday being a rainy day seemed an ideal day to make a start. After disconnecting all the pipework and the two screws holding it to the wall I then cut through the mastic sealing it to the tiled wall with a Stanley knife and attempted to lift it of the pedestal but with no success as it was still stuck fast. I discovered that whoever installed it had put strong mastic all across the back of the flat 60cm X 15cm back of the basin which abuts the wall and also between the basin and the pedestal. I've tried getting a long blade between the basin and the wall to cut the mastic but the gap is too narrow. I don't want to damage the tiles as they were expensive. ANY ideas please as I've run out of them?