Hi Ollie. Did you end up using that set off wiring for the radio in your picture? (Appreciate it's nearly a year ago!). It's just that I'm looking for one of those link cables with the round connectors at each end for my cassette player, which I'm hoping to put into my XR3i (not a cabby, sorry). I have the cassette player and equaliser, both with the round multi pin sockets.
Cheers,
Lee