if your going to put new tiles on the wall why do you need to take the work top off? can you not just tile from the worktop up. Anyway, the HOB can be Clipped into the worktop with a screw clamp, if you look under your sink,see the clamps that holds it tight to the worktop,you screw them tight and the teeth on them bite into the underside of the worktop, to hold it on, when you unscrew them they open the bite and you can take the sink off, the HOb should have the same should have the same clamps, but sometimes they just cut out the hole for the hob and silcone around the edge and drop it in,just turn the power off the the hob first, and get a look for the clamps unscrew them and lift the hob out
n, September 2014