The basin can often be gently propped up just enough to slide pedestal out by cutting any visible silicone or by the hacksaw blade method or pad saw / pull saw . As silicone is quite dense it tends to cause a lot of resistance ( like cutting through a rubber car tyre ) when trying to cut through it. smashing it out could open up a can of worms as not all plumbers immediately reach for the silicone. Other pipes or cables could have prevented it being fixed by the usual methods .keep as much intact as possible but be prepared to replace basin and pedestal if the hits the fan .. back to your basin you should be able to remove it once ghe pedestals out of the way or even partially. Replace trap ( 32mm ) with a telescopic type if in any doubt ,,