Standard practice in this sort of case to send a loss adjuster out. It is not unknown for people to inflate their insurance claims and the insurance company will need to assess damage caused by the leak and damage caused by 'wear and tear'.
You say it needs new kitchen units, just how deep was the water? They will want to see if just the legs and plinths need replacing and assess the quality of the units if they do need replacing.
They will also need to assess the damage under the floor - the floor joists, foundations etc.
Here is a brief but useful summary of the claims process
https://www.morganclark.co.uk/about-us/blog/how-to-make-a-successful-water-leak-insurance-claim/
By the way, if you do need new base units don't expect the insurance company to make sure they match the wall units.