Hello Hifipete,
If you want more power, The Spectron Musician III MKII mono-blocks will output 2400 Watts at 8 Ohms, 3200 Watts at 4 Ohms, 5600 Watts at 2 Ohms. Despite all this power, there is no sign of overdrive at all. Just pure, clean, well-controlled and refined sound.
With the Bel Cantos, you may also be able to use four Ref1000 amps as I've seen at shows.
Best,
iSanchez