Hi Alan.
I think that Essential Service is a good choice for older vehicles, as yours now is.
Your upcoming service is 60,000 miles I think, so that`s biggish and the costs is on the Lexus website.
I think that a Lexus DEALERSHIP will disclose a problem, if indeed, one exists, regardless of whichever you choose and they will identify and show it to you.You then have a choice--have it done or not. At Lexus or an Indie you can trust.
I have all of mine done at Lexus Chester--a small dealership and not part of a Group.--and they have never tried to tell me that something is wrong.And besides I have the cover of the Extended Warranty for the cost of the equivalent of £45 per month.
Perhaps you should choose that now before your next service ? Good luck.