Update to my thread, as I've got a bit of time on my hands at the moment !
I decided on the Grom interface option, rather than a replacement head unit, as I only really listen to two radio stations in the UK and listen to music from a USB device, which is what I would listen to on any Euro trip. I also included the Bluetooth interface option as well.
Installation, pretty straight forward, just remove the centre console and associated units, found a place to mount the Grom unit and wire in the phone microphone next to the rear view mirror.
I could've done the whole thing in one day but the Mrs suggested that I might want to drag the job out over a few weeks, as the chances of getting the car back on the road for the beginning of April, was not going happen. So the job was started a month ago and finished this morning.
Mounting the Grom unit.
Routing the wiring for the microphone.
Testing the USB.
USB connector in centre console.