gapping of plugs on zafira gsi

Hi Again guys,ok done oil change,coolant change,air filter,wipers,just gotta fit ngk irridium plugs which should be here tomorrow what size gap should the plugs be,i realise i can do them to what they are on the car now just wondered if you guys gap them differently,i only have the normal zafira handbook from dealer and doesnt say what they should be anyway,any ideas??
Thanks very much

Dave