RCD300 aux in very quiet/CD changer not working?

[probedb]

Slowly going through the issues I've had with the 2005 MK5 GTI I bought a month or so ago :) Next one on the list...the stereo.

It has an adapter in the glove compartment, 3.5mm plug and old style iPhone/iPod connector. These are selected as disc 5/6 on the CD changer.

Problems are that the 3.5mm socket input seems to require a lot of current to be loud. Turning the stereo volume to max and my phone (Galaxy S8) volume to max is still lower than the CD input at half volume. Just wondering if there's any reason for this?

Second problem is that CD changer doesn't work at all, the LOAD button does nothing :/

Am I going to have to get the head unit out to see what the adapter is like and ditto with the CD changer? Are they easy to remove?

TIA!
Paul.

[probedb]

Have worked most of it out. The aux and ipod cable come from a Dension Gateway 100 which means the CD changer is unplugged which is why it doesn't work :)

I also have a Parrot BT unit which seems to be worth a sensible amount. However I've discovered Dension do a newer version which has BT built in and can also play files from a USB device as well as allowing various addons like an iPhone lightning connector, aux 3.5mm etc.