Part P required? Changing Fixed Oven wiring to 13A FCU (UK)
Since April 2013 a kitchen has not been a special location under the amended Part P of the Building Regulations. 


  Under the new, revised regulations, electrical work undertaken in
  kitchens such as adding a new socket or work outdoors such as
  installing a new security light will no longer be notifiable unless a
  new circuit is required.


https://www.niceic.com/Niceic.com/media/Schemes/NICEIC-Part-P-Updated-Factsheet.pdf

The work should still be done in compliance with the IET Wiring Regulations, but need not be notified to Building Control.

What you, or the person doing the work should do, ideally, is carry out basic testing on the circuit (polarity, earthing) and make out a Minor Works Certificate accordingly. Templates of MWCs are available free online, but to do the testing in strict compliance with the Regs would require a calibrated tester.