I know that in June 1942 No 6 Sqn attacked an armoured column of tanks and half-tracks in North Africa (can't remember where) leaving more than 15 vehicles destroyed for no loss and also in March 1943 a squadron of Hurricane IIds (6 squadron again, I think but I aint got time to check), operating in North Africa, destroyed around 30 Axis tanks in three and a half hours. There are other examples but these are the only ones I can think of just now. I have some footage on video of IIds attacking armoured columns and they appeared to be very effective. They 'walked' the .303s up to the target, then opened up with the cannon just as the Browning rounds reached the target. Also, the muzzle flashes were pretty rapid (faster than AH model?), and no, I wasn't mistaking the brownings' flashes for the Vickers'. I've heard that IId pilots had to point the nose down when firing the cannons because the nose tended to pitch up when they were fired. In real life it was certainly anything but useless against ground vehicles.