I fitted a Bluetooth receiver in place of the radio but found I couldn't hear anything when we got going due to wind noise, I searched for an amplified receiver but they tend to be bulky and expensive (more than a Yorkshireman wants to pay anyway), I eventually found one on Amazon and fitted it under the dash with double sided tape, it's quite small and I can now hear sat nav instructions over the wind noise, I have to turn it down when I go through a town as it startles pedestrians.
Search for tpa3116d2 amplifier board on Amazon, there are 3 variants one goes to 100W, I went for for the 50W middle option.
Regards
Mark