I'd hold out for a RCD510 or RCD510 DAB on here in the For Sale section. That usually go for around the £200 mark on here so so difference in price. That unit doesn't seem to have a phone button, not sure ifBluetooth can be added, someone will be along to correct me if wrong.
Depending on the year of your car, you might need a new gateway otherwise you might get battery drain. I think if your car is 07/57 onwards your fine but best to check with someone who knows.
You'll need a FAKRA antenna adaptor (on eBay for around £10) and some coding IIRC but that's it.
looks like this....
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