Well guys I've been very lucky, and the events after my mirror was smashed off has slightly restored my faith that there are still some good people knocking about! The owners of the other car have decided to go through the insurance and have admitted full liability for the damage (He sent me a text to make sure I had it in writing). Within 10 mins of the text, I had a call from their insurance company (Direct Line) accepting full liability from their POV and arranging full details to allow them to get my car sorted.
Saturday morning I had a call from their repair team, booking to collect my car from my place of work on Wednesday morning, followed by a call from Enterprise who will be dropping a hire car off on Wednesday afternoon.
I can't fault the way it's been dealt with so far, and fair play to the owners of the other car for dealing with it in the right way.
Let's hope the repair is up to standard... I won't be accepting it back until it is!
I will most certainly be fitting dash cams to both mine and my wifes cars ASAP.