The phone number to opt out of auto renewals is: 01302 565532 OR you can change your preference in the My Policies section of the website portal. I think this option closes once renewal documents are sent out.
Tbf, I've been with them a number of years for my bike insurance, and they were excellent when I had a no fault claim a few years back.
It is difficult to get hold of a 'real person' though for anything other than claims and renewals.