I'm completely ignorant about these things. My current cooker has been in place for almost 12 years. So I have no idea if the wiring is up to date. I do know that questions answered on the Argos site indicate that all cookers need to be hard wired.
And I'll repeat again...I will not be doing it.
I was in Currys the other week and noticed that many of the the cookers came with a 13A plug ready fitted, just stick it into the socket on your cooker point.
danny.....if your consumer unit has the capacity and is compliant regarding rcd/mcb protection etc there is no need for a separate box..I can only assume that yours may have been non compliant or full to capacity.