Yeah Slaw, consider yourself fortunate to have nabbed your Rock! They don’t come up for sale often, their owners often never finding another table they would rather own. I hope to someday find a Rock Reference, reportedly the best of all versions. Except perhaps the upcoming one!
Noromance, the darkness you heard in the original Rock is probably why some people use lighter gauge silicon in their trough, others filling the trough to a lower level, both done to achieve less damping. The over-damped sound is likely one reason the Rock works so well with Decca/London cartridges, which can sound brash (especially older Deccas, and even moreso if they aren't loaded at 15k to 22k resistance and some capacitance, to flatten the high frequency resonant peak the cartridge has). I've heard the Mk.7 Rock, but only at shows and with unfamiliar LP's. It's undamped acrylic platter may have something to do with a brightness, which is not the case with my Elite's platter. It has an acrylic coated top, but is a plaster-of-Paris filled metal disc. No ringing in it!