No certification of electrical work as was only installing lights and not rewiring?

It should be good working practice to issue a minor works certificate as a minimum to show that testing has been carried out and test readings recorded. From the sounds of it no tests were done and the job was just a quick as possible in and out. Did you confirm using a registered electrician/ was the main original concern to accept the cheapest option you could and worry about the other issues afterwards. The client that go for the cheapest option usually get what they pay for. For future reference use this site http://www.electricalcompetentperson.co.uk/ every registered electrician in the country should be on it, you can find electricians by name or location.

Most electricians will supply a Minor Works Certificate for these types of works. These types of works are NOT notifiable to building control (Part P)

Yes that's correct, a Minor Electrical Works Certificate is required as the circuit in the kitchen and lounge has been altered by virtue of adding additional lights. Sounds like a cowboy and not a proper Part P registered electrician.

Any work installation work in the kitchen is notifable and MWC should be issue MK of Fulham Electrical