New oven and hob

[P.J.]

Hi All,
I usually do my own electrics and planned to do the job described below and then get it inspected.
I'm changing my old slot-in gas oven/hob unit for a built under electric double oven and separate gas hob. I've scoured the old posts with the search facility and found out some useful stuff, but have a couple of other questions to ask:
There's an existing single socket behind the oven, I'm planning to spur the oven from the socket with 2.5mm 2 core and earth (the oven is 4.11KW) but how can I tell if a suitable supply is going to that socket ?
Also, the hob manual states to fuse the connection with 3A, but doesn't mention the use of a 3 pin plug. Can I just use a 3 pin 3A plug and plug it into the existing socket behind the oven or do I need to hard wire to a junction box for example to conform to regs ?
Much abliged for any advice offered.
Thanks,
P.J.

 

[P.J.]

In case anyone was waiting for similar advice.....
I had a sparkie round and he said the following:
The supply was enough for the 4.11KW oven as there was 6mm^2 cable running to the oven isolator switch above the worktop.
I need to change the 3 pin socket under the worktop to a Cooker Outlet that fits in the same switch box (you could wall-mount this), and then hard-wire the cooker to the outlet with enough cable to let you slide the cooker out for cleaning/service etc.
He found that a spur had been fitted from the socket on the cooker isolater switch and said this is not allowed because of the higher power supply to that point. You would have to spur from a normal 13A socket to correct this.
Hope this helps, any advice regarding the above
Cheers,
P.J.