Speakers to big room

NEver heard those Tannoys but they look very nice!

Are you sure you have the right amp to max out the performance with those speakers? I am not familair with your amp so cannot say, but I would confirm that first before changing speakers if you like the sound but just want to make it better. IS you amp a tube or SS amp? 240w/ch to 8 ohm may be overkill for efficient speakers. Maybe there is a better match with lower power output? Speakers like those that use large drivers often do best with an amp with higher damping and current delivery as opposed to just pure watts. These are some things I would be sure of first before changing nice speakers like those that you already like.

none of the speaker you listed as alternatives are high sensitivity designs

I know tube amps are popular with high sensitivity designs like those, but I wonder if insufficient damping could be the culprit? Tube amps have higher output impedance which results in lower damping. Have you ever tried a SS amp with very high damping factor for comparison? I would expect much different sound in that larger drivers often benefit from higher damping resulting in cleaner and more articulate bass. Maybe better overall, maybe not.

A good Icepower Class D amp might be interesting to try with those Tannoys for that. Since they are high efficiency, you may not need many watts, just current, damping factor, and higher input impedance also if you are also using a tube pre-amp. BEl Canto ref500m monoblocks come to mind. These have a good rep and make improvements on stock Icepower power supplies and input impedance for use with tube pre-amps. I use larger BC ref1000m monoblocs with my lower efficiency OHM Walsh 5s, which also use a larger driver tha benefits from higher current and damping.

O,here is specifications for my amp,I think you can't get anything better then this($30k),this amp is state of the art product.