I'd be surprised if the insurance actually required anything much at all, but perhaps best ask them.

Legally in England, (less clear in Wales where as work in a kitchen it may be) such work is not notifiable to anyone in particular unless you are creating a whole new cooker circuit from scratch, you just have to be competent to perform maintenance and replacement tasks, which this sounds like.  Assuming you can follow the makers instructions and use the right size and type of cable, you can just get on with it. An MWC is never a bad idea as it is a record of who where why and what, but its not mandatory. Do check the thing is earthed - its the sort of thing that seems to fail and not get noticed in older set-ups

If it is an induction cooker be aware that some models don't play nice with RCDs and it may need its own RCBO or RCD rather than to share.

Mike

I understand that wiring regulations have tightened and the install will require a minor works cert.

Depends if you're simply connecting the cooker to an exiting circuit (say at a connection plate), or installing a new circuit from scratch. The latter would require an EIC rather than a MWC. (The EIC would of course only have to cover the new work, not the entire installation.)

free standing cooker 3kw+.

Just checking that we are taking about a full "cooker" here - 4 rings, grill and oven in one big floor standing box kind of thing. Just that usually they're rated at a heck of a lot more than 3kW. Rather than say a counter top cooking appliance (e.g. a pair of hobs and perhaps a grill) that can often just plug into a socket.

  -  Andy.

BS 7671 requirements for certification haven't changed much for a very long time. But more recently, depending on where in the UK you are, there might be part P of the building regs to contend with (or equivalent) - mostly creating a new circuit is notifiable to building control - which either means paying a (substantial) fee beforehand, or getting a registered competent person in.

  - Andy.

James Hartland said:

I have been asked by a family member to install a free standing cooker

Are you expecting to get paid or just get a cup of tea and a biscuit?