BAT REX 3 with Harbeth 40 series

I take it you don't have the opportunity to try the combination.  I've heard the 40.2 at a local dealership that sells only tube amplification.  This is an extremely touchy speaker that can sound soggy and lacking in dynamics and loose in the bass region with some amps, but not others, and it not necessarily the case that the more powerful amp sounded better with this speaker.  This speaker, more than most, requires auditioning with the particular amp in mind (I don't know if this is the case with solid state amps).

I don’t have a local dealer unfortunately.   I have tried a 250 watt tube amp and it’s quite amazing with the Harbeths.  

i have found the mon 40.2 needs solid state amplification to do the bass really right - have not tried victor's bat's though... they should have among the best damping factor that tube amps can provide, along with my arc amps, but best tube amp damping factor does not remotely equate to that of top tier ss amps