It does look odd, but I don't think it's possible to be completely sure one way or the other without a photograph with the busbar cover removed.
i'm completely sure, as explained previously I looked with my eyes and the bus is off the positive, but if it helps put this to bed and direct the attention to the enquiry first raised ill photograph later and upload
Are you happy you know what you are doing from your initial enquiry?
Its all been an interesting learning curve, the initial question of 'is it incorrect for a mcb to share a kitchen radial circuit and a feed directly to an oven' the answer appears to be clearly no, an individual mcb for the oven is recommended and is preferably rcd side of the consumer, which all makes sense. thanks for everyone's input.