OK to have double plug socket 600mm above gas cooker?

No this arrangement is not suitable and a socket directly above a cooker would be non-compliant with BS7671 wiring regulations as well as being a potential fire risk/safety hazard. The socket should ideally be 300mmm to the left or right of the cooker so any plugged in equipment and cables are safely routed away from the source of heat from the burners. Best option would be to relocate the socket if at all possible.

Dear Chris, BS7671 does not state these distances but the main risk is operational risk, as if you have socket above and something is plugged, and someone wants to operate the switch while something cooking, this can lead serious burns or injury as it's posing a health and safety risk. In my considered opinion, you may have a problem. Whilst there is no direct regulation, an IEE publication called Electricians Guide to the Building Regulations shows on page 61, Fig. 5.2, a distance of 300mm between the hob edge and socket outlet. Also, 300mm between the sink drainer and socket outlet. The other thing to consider here, is the socket likely to be splashed with water? In other words, is it suitable for the environment. Same would apply to the socket over the hob. Will the socket be subject to steam ingress? Will the cables or socket outlet be subject to excessive heating? Almost certainly any appliance plugged into the socket over the hob may have its flex damaged if the hob is being used. Above 600 mm there will be no more than average 40 degree cooking temperature therefore the socket or other electrical wiring will not catch fire. Example: Cooker hood above 600 mm have motor and micro connection and switches have you ever heard this got fired! Example: Central heating pipe work passing next to all type of wiring under floors everywhere in UK some time less than 100 distances never get fire!! Again it's operational safety issue. All the best, be safe, hired only experienced, qualified to current regulations and HONEST person to grant permission to touch your wiring.