After seeing someone else in one of the groups do it, I decided to "upgrade" my multimedia using a cheap 8" tablet to interface with the Sony aftermarket stereo. Setup Agama car launcher as the shell on the tablet. Works pretty well and the Bluetooth connection works well for audio, satnav etc.. Tablet use a 4G SIM card for it's data
Aim was to make it interchangable with my phone. So it sits in a std clamshell phone mount (top of clamshell holds onto "popcap" on rear of tablet rather than top edge of tablet)
Only thing I still need to sort is ignition controlled power supply on dash and an app like "automate it" to hopefully power the tablet on/off based on the status of the USB power