Thanks to another member here, I fitted a GROM BT3 adaptor to the Alpine head unit today.
Took it slowly and it went really well and I didn't manage to break anything.
The bonus is the sound quality .... I couldn't believe it would sound so good playing mp3 from my Android phone.
I have also downloaded Neuron music player fro Android which claims to access the dac in the phone directly and also do some other nice audio tricks.
Now to fit a tablet in the dash if I can sneak it past the War Department!