So several days later (and one year older myself!) I've been in touch with Suzuki UK, Panasonic UK. the helpful ProgressiveIce.com, and the very helpful Cellustar Ltd. Let me outline what I've got so far...
According to Suzuki UK, "We do not deal with that kind of enquiry, sir; you will need to speak to your dealership." But my dealer told me to ring you... and they still can't help. Rude bloke, as well.
Panasonic UK were helpful to the extent that, of course, they have no knowledge of this radio (it was worth a shot), but I do have the numbers of Panasonic Automotive Systems Japan (Japanese speaking voicemail system, despite assurance they speak excellent English there). But from my experience, it sounds as if they were closed at the time.
ProgressiveIce.com are the UK importers/distributors for Dension, and specficially, the Ice>Link Plus and the Ice>Link FM.
The Ice>Link Plus is supposed to work with factory-fitted headunits, by fitting into the car radio's CD-changer port. In most setups this even shows the ID3 tag from your iPod on the radio display. Unfortunately for me, they do not have a kit for the Suzuki - and this is apparently the reason why. (The guy I spoke to seemed to know what he was talking about.) The radio is designed from the Vauxhall head unit. Dension actually worked with Vauxhall to try and design the kit, to the point where Dension UK were given a Vauxhall Tigra so they could try and set the kit up. But it just won't work, so Dension have given up.
However, ProgressiveIce did suggest the Ice>Link FM, which fits through your cars FM aerial allowing you to 'tune in' via one of three fixed frequencies. (As this is direct fit, it is legal in the UK).
Finally, Cellustar Ltd (
www.cellustar.co.uk) make a 'Radio Mute' and non-destructive mount for the Suzuki Swift 2005. And having spoken to them today, they are not just helpful, but very knowledgable. The mute fits between the connectors on your radio, to a mobile-phone handsfree kit. You will need to make sure you get the proper type of phone holder that allows a seperate audio out and mic input, but this should not be a problem for most people.
Any other finds regarding the car radio?
J