Connecting Quad99 CDP-2 to Quad 909 amp via Quadlink - won't come out of standby mode

Hi folks. I recently purchased a Quad CDP-2 as well as a Quad 909 amp. When I try to connect them via a Quadlink cable, the 909 doesn't come out of standby mode (red LED). As soon as I pull the QuadLink cable out, it comes on just fine (green LED). Most posts I see talk about also utilising the CDP PreAmplifier n a setup, but I have found one listing from hifi4sale where the seller says they connect these two bits of kit just fine. https://www.hifi4sale.net/t21416-quad-99cdp-and-quad-909-poweramp-used

I also have a Quad Elite CD and Quad Elite Powered Amp, and the Quad Elite CD talks to the Powered Amp via the Quadlink cable option just fine.

So I'm thinking there's possibly something wrong with the 909 or the CDP. I have tried 2 quadlink cables (although not the one that my Quad Elite system is using, so I guess I could try that one too).

Any suggestions from anyone? Anyone had the same issue?