I removed the 3.5mm jack, cleaned the contacts with a fibre glass contact cleaning brush, and then cleaned both the audio connector and the gold plated PCB pads with IPA, reassembled, and everything worked perfectly. Thanks for the guide, it’s boarder line perfect ;-)

It needs to be made a little clearer that the thin metal retaining ring needs to be unclipped before pulling on the D-pad. A small, flatbladed screwdriver did it nicely for me.