Britanna SI-10TC-SLX-K. No power to main oven

Good morning all. Apologies for the long post. We have a problem with the above make/model. We were waiting for the main oven to heat up when there was a bang followed by a puff of smoke. All the electrics tripped. After resetting the electrics, we found the main oven to be dead – no element, fan or timer operating. The second oven and the ignition for the gas hob all fine. I had previously replaced the element some 18 months earlier, but in that instance it was just the element that didn’t work – the fan & timer were ok. Easy diagnosis and repair. This time, after isolating the electrics at the main fuse box, I pulled the oven out and removed the back to remove the element so I could have a close an proper look at it. It looked fine, and using a circuit tester, showed it was a closed circuit. Looking at the rear panel, I noticed that there were two burn marks just inside the panel (where the element connectors are) and the wires to the connectors were very loose – so loose they separated very easily. I should point out that the element that was replaced last year was not an OEM part and that the connectors on the element were longer, so probably contributed to the problem described. Anyway – made the connectors all good, reconnected and restored power. Same problem. Researching this, it points me in the direction of a number of possible causes …. the element itself, the fan motor, the thermal overload cut out, the thermostat or electronic control board. All individually costly – if I use OEM parts, which given my experience so far I will probably end up doing !! Does anyone have any suggestions or thoughts? The thermal overload cut out was found/tested and seems Ok. Any advice. guidance appreciated. Thanks in advance