I'm tending towards an Neutral/Earth fault. This need be nowhere near the appliance you were using when it tripped, the trip occurs when you are using enough current for the %age that leaks to reach the tripping point.
It's unlikely to be in the cooker, I think, unless the cooker had been standing unused for long enough to get damp, or had been washed down.
It could have been an accumulation of small leakages, but these would most likely have been in watery appliances like washer, dishwasher, kettle and immersion, and your PC, TV and chargers, so would go and return when you unplugged/re-plugged them (the switch is not enough). If your immersion or heaters are on a timer this can change the results.
There is a risk of "not my fault" if you get a cooker repairer in but tripping still occurs.
If it happens again, unplug everything else and see if that helps.
The next step would be to call an experienced qualified electrician who can test or leakages on your circuits and appliances. Start with a personal recommendation, then look them up on their Competent Person register such as www.niceic.com/ to check them.
You want someone who is not just a Domestic Installer (this is the lowest grade) and has some years experience.
There are several registration schemes, firms usually display the name and logo of the one they are in.