What Is The Best Way...

[rsgaz]

MP3 ... ... does not have an AUX socket.

It's more complicated than that I'm afraid, some can have the adapter cable fitted and some can't.

Look at the pinout digram, this one can...

Both of those made by Grundig(rather than Blaupunkt), both from 2006, both the MP3 models, and yet different pinouts!!!

 

[ellal]

We've got one of these: Link

Works quite well for streaming, although using it for calls is a bit hit and miss volume wise depending on where you can mount the main unit and balancing the phone volume.

Interestingly the first review mentions a CD30.

 

[mattylad]

They are of course, not legal to use in the UK. (WTA - your transmitting on broadcast frequencies.)

 

[SammyInnit]

They are of course, not legal to use in the UK. (WTA - your transmitting on broadcast frequencies.)

That's not true.

In the UK Stautory Instrument IR2030/26/2 2011/0401/UK (from December 2011)[6] permits unlicenced use of devices that can be shown to radiate less than 50 nanowatts (-43dBm), on a 0.2MHz raster in the range 87.5–108MHz.