If it's a 6 (gas) hob cooker it's going to be a range cooker, so will be double oven and grill, and possibly an electric hot plate.
So sticking with a 13A plug is not a solution.
If you don't have any test equipment and testing knowledge, get an electrician in.
Could be MCB tripped, Fuse blown, faulty cooker switch or wiring fault.
An electrician should logically test it through and determine the problem quickly.
Post some pictures of the CCU, cooker switch, and your fuse box.
If your cooker switch also has a socket on it, does that socket work?