I have heard Tannoy Westmister Royal with Super Tweeter some years ago on High End Audion show in Munich.
They were powered by Accuphase Class A Amplifiers and source was Accuphase CD Transport and DAC.
These were Best /by quite a margin/ speakers on whole show and overall best speakers for pleasant listening existing
Some years later I got my 15" Dual Concentric Tannoys /in bass reflex and not horn casing/.
They are also great overall, but high frequencies are not really up to level of modern speakers.
Even putting Treble Level and Energy knobs on speakers to higher settings.
Comparing them to modern Dynaudio Monitor speakers, my Tannoy sounded like mud in high frequencies..
I thought that my tweeters might have burned out.
After doing measurement with REW and calibrated mic, flattening curve and dips with parametric equalizer and fixing highs, now they sound great also where they were lacking in high frequencies.
So looking forward for day when I will have the chance to replace them with Westminster Royal