I am getting a John Lewis 3.5KW Pyrolytic single oven JLBIOS613. There is a dedicated 6mm cooker circuit with a 32amp RCB. Also 20 amp cooker switch. At the moment behind the existing single oven there is a double 13amp socket wired to the cooker circuit and supplying the present oven and the gas hob. Is it OK to connect a cooker connection unit for the new oven which is rated an 20amp and connect the existing double socket as a spur for the hob? What size cable should I use to connect the new oven to the cooker connection unit?