I have a new Bosche oven and existing gas hob. The original cooker and hob ignition are both connected under the worktop behind the oven with a double gang Sw/Skt and plug heads. They both plug into it. The switch socket is fed from the cooker control switch above the work surface with 6mm cooker cable. The max fuse feeding the cooker is 13amp and has only a flex leading into the cooker... Is this correct?
I assume your in the U.K as this sounds like a typical set-up for cookers in a kitchen area. The circuit feeds a control switch or cooker unit switch which may incorporate a one socket-outlet. The rating of the circuit depends on the current demand of the cooker. A 32A circuit breaker is normally sufficient for cookers up to 15kW. Wiring a cooker circuit with a rating more than 15A but not exceeding 50A may supply two or more cooking appliances where they are installed in one room. The cooker switch should be installed within 2m of the cooker but not directly above it. One switch may be used to isolate two cooking appliances where they are installed in the same room but neither are more than 2m from the cooker switch. A minimum cable size of 6mm flat twin & earth cable can be used for a typical cooker circuit (from the CU) with a maximum load of 15kW with a maximum cable run lenght of 28m (installed above a plasterboard ceiling covered by thermal insulation not exceeding 100mm thick).
In summary make sure to check the new appliance is the correct power/current rating. However normally to replace like for like is perfectly fine