Installing Grundig MCD 40 for a Symphony Radio Unit

Hi

Recently taken out a Grundig MCD 40 (10 Stacking CD Player) out from our old Octavia to fit into my Fabia. The CD player that is in the Fabia is a standard Symphony CD player (6Y0035156C) which has the free socket on the back to plug in a stacker. Checked the manual to see whether this can be done, & found a wiring diagram through this site for it and everything 'should be' fine.

Having plugged it in the Grundig refuses to work, but the radio is happy to work with it plugged in.

Does anyone know the next steps for something that should of been nice & simple?

Many thanks

Harry