Big problems after bulb blow tripped out mains,CDA range

CDA CD9000/2 dual fuel range ,Last night after cleaning cooker realised bulb cover was grubby so took it off and cleaned and replaced,turned light on to check,, didn’t work so tried bulb it felt lose. Gave it a twist and there was an almighty bang then darkness,after checking that I still had all digits intact, went to my main fuse box and saw I had no power at all, checked the pull out fuses in main box and it had blown the 30 amp, so I replaced the fuse wire and replaced it, still darkness though, so rang the council they sent a chap out and he deduced it was the main 60a fuse to the house, so then had to ring my supplier they sent someone out who arrived at about 3.15 am this morning, he replaced the main fuse and lo and behold we had light, went to cooker point and turned it back on and the was a bang again,and a little puff of smoke came out of back,and it blew the 30a fuse wire, so left till today and took back off removed bulb holder and found some remains of the bulb the was probably causing the short for the second bang so left it disconnected,also found a round rolo shaped thing on the back with 2 terminals on and there was signs of smoke deposits on it and the two red wires that attached to it, one of the red wires had detached its self, so I touched it back on to remains of terminal and bang again and the rolo thing detached it self from back of oven, so I again replaced the 30a fuse wire, and have power back to cooker, timer/clock is working fine and gas burners ignite fine, it’s just the oven/grill that is not working, anyone able to tell me what the rolo shaped thing would be and if I replace it will I be up and running again, any help would be appreciated as CDA want £89 call out,