Things are worse than previously thought: the local reference range for fT3 is 3.5-6.5, not 3.5-5.5 as previously thought. Whether twas ever thus I don't know. But it means my fT3 is in worse shape than suspected with my last reading of 4.3 putting me a gnat's over quarter of the way in range rather than just under halfway.
Plenty of scope for more T3, though. I'm now more convinced than ever that my T4 has pretty much stopped converting.