I replaced the battery a second time just in case it was a dud, and checked its position against the original, so I think it is in the right way. I also checked all of the wiring connectors to make sure I had not partially pulled one out. However, I will do that all again to be certain it is not something that simple.

Thanks for the input,

Ross.

Control:15, TwinStore 2GB*2, 500, Auralic Vega, Pass XA60.8 x2, B&W 802D, Stax lambda & SRM-T1S, Prime Headphone Amp., HiFiMan 500