Having recently bought the FVP-5000T I have received my first request to retune the recorder/player.
Unfortunately, Freeview Play -> Settings -> Channel Settings does NOT allow either Automatic or Manual Channel Search. Both options are permanently greyed out(*)
Thanks for your reply. You must have been correct because, taking your advice, I waited until I was absolutely sure nothing was either being recorded or about to be recorded, and Automatic Channel Search became available:-)
And then a Smart Retune did the trick (none of the multitude of scheduled recordings were lost:-)