JAGUAR X350 XJ - NO SOUND FROM RADIO/CD - D2B FIBRE OPTICS

I have bought a used 2006 Jaguar XJ Sovereign X350 Model, with alpine sound.

Was getting no sound from the radio, and CD.

Firstly checked all usual audio related fuses, all good - still no luck.

Ordered a new AMP online, thought this would crack it, again no luck.

Delved deeper and stripped the full boot out, checked all the fibre optic connections to CDC, VOICE, NAV, PHONE ETC, on the stack on the left hand side.

All were ok, I thought I would of had a faulty module in the stack, so basically looped the CDC, VOICE, PHONE, all out the network, so only from the wiring loom in the back, connects to the amp, nav, and back. This has been done many of times online and solved the issue by cancelling out the modules with fault.

Still nothing! Even went and tried another AMP that also didn't solve the issue, that's 2 Amps tried now (thinking the first replacement may of also been faulty).

We are getting a red blinking light from the male end in the rear of the boot, so from the head unit to the boot we are getting light through, so cannot be a break in the system there?

It's getting quite frustrating now and not getting where. Any help would be much appreciated. Could it be a faulty headunit? Door speakers?

Doing the EJECT, MIX, button on the headhunt, I get MAIN, and DTS. - nothing else

Thanks