Really need to know the rating of the cooker, and what other loads are on the ring.
A 20A cooker, will not on it's own overload a ring. However a 30A cooker anywhere outside of the middle third of the ring, will cause one leg to be overloaded.
If there are other high current appliances connected to the ring, they will also affect the load on each leg.
With the lights, we need to know the CCC of the cable.
If it's greater than 10A, then no code. If less, then code 2.