HI THERE CAN ANYONE HELP ME WITH FIXING MY SMEG GAS HOB. ONLY 2 OF THE RINGS ARE BURNING. THE IGNITION SYSTEM IS WORKING TO EACH OF THE 5 RINGS BUT ONLY THE 2 FRONT SMALL RINGS ARE BURNING. I HAVE TAKEN THE REMOVABLE PIECES OFF AND CLEANED THEM BUT STILL NO LUCK. REGARDS AND THANKS