Gas hob is fine, I mentioned this to illustrate the point that it is working, and wired into the sockets which also serve the oven, which is as follows:
*1 wall mounted double plug. in left plug is a white plug, with two cables wired into it,
right plug has one black moulded plug - both plugs are switched on.
The cables disappear into a hole in the housing unit close to the left of the plugs.
I cannot therefore find any clues as to what links to what.
I am concerned about the two cables wired into one though.
*1 square wall mounted box to right of double plug with a switch, showing 'switched on'
to its left, on the same face, a small flush oblong outline, with the word fuse written on it
Can I email a photo - it may be easier to visualise?