Peter,
I'm not sure if you are still considering change but..
As a LEBEN owner myself - LEBEN CS300F and RS30EQ combo - I could heartily recommend them.
But first, your SUGDEN amp is no slouch... Having owned the Ray Samuels F117 Nighthawk myself for a few years, I think you might be quite surprised how a better phono stage could improve things a lot.
Whilst I am a fan of the LEBEN RS30EQ Phono Stage, it could easily be guilty of being too smooth in the wrong system, so I would recommend that you check out the TRICHORD DINO and TRICORD DIABLO Phono Stage options with their NEVER CONNECTED POWER SUPPLY.
I say this, because we still run an earlier TRICHORD iteration - the TRICHORD DELPHINI MK. 2 - 2 CHASSIS PHONO and frankly, it is very hard to go past.
Just a thought...