I haven't done so and I won't be doing so. I am using the approved size and speed-rated tyre as specified in the handbook and on the originally supplied wheels. As an engineer, that is not a modification. That I would argue in court if necessary with, no doubt, a tyre engineer from the tyre manufacturer (Continental) to back me up
If I had fitted different diameter or width wheels that would have been different, but in the case of a straightforward change there is no change to the insured risk.