Graham, to the best of my knowledge and belief, Lexus U.K. has not made any such claim.
Anecdotally, these people have;
the Lexus Salesman
the Receptionist
the man on the Service desk, etc.
Nemesis is quite right to mention T&C always appearing in formal Lexus announcements re Relax.
None of us will know how good the new warranty is until we have had experience of it.
We (those of us who currently participate in the current Lexus Extended Warranty Scheme), do know that Relax is not as good. The proof of the pudding is in the eating and we shall just have to taste the Relax warranty and see.
There is no evidence that Lexus U.K. has claimed that Relax is anything other than a benefit available to certain Lexus owners for a certain period of time and miles and is free of charge.