Oven power is off :-(

[conny]

NO! Just because the oven display is off does not mean the supply is off!
This is clearly shown that the MCB is still in the on position so the circuit is still live.
If you don't have a multi-meter, or some other form for testing if a circuit is live, then the only alternative is to switch everything off by the main switc in the consumer unit, (fusebox). This will allow you to check for loose connections behind the faceplate of the cooker outlet and the socket outlet which your warmer is connected to.
Have you tested something else in the warmer socket as suggested by Andy? If not then try that first. If it works then it points to the warmer being at fault. You can check this by plugging the warmer into a different socket that you know works. If the warmer doesn't work then it is at fault.

 

[dannyboi2003]

The red switch on the left for the oven appears to be a different brand to the one on the right, probably insignificant but could point to it having been replaced previously. I'd turn the power off, open up the switch and check for any loose connections behind, socket for the warming draw is likely fed off the cooker plate, worth checking that too.