It is, the Relax Warranty is up to 10 years or 100,000 miles. After this, the Extended Warranty is up to 15 years or 150,000 miles.
I just sold my 110,000 mile RCF which was still in excellent mechanical condition (as expected!)
I’m not sure on the legalities of selling a used car as a trader to a retail customer without any form of come back if anything goes wrong. The CRA 2015 provides certain protections to consumers in this instance, even without an explicit warranty agreement. I don’t believe that simply stating it’s a trade sale basis would relieve a trader of their legal obligations!