1. You don't need solicitors to deal with the damage to your vehicle.
2. He doesn't have to settle away from insurance.
3. Your best option is to approach his insurance company direct. Explain that their insured is in the wrong and that you are approaching them direct as you'd sort it out fairly than using your own insurers who you both know will milk the claim dry. Tell them that you simply want a speedy and high quality repair and ask which garages (plural) they propose. If they don't offer anyone you fancy tell them who you want to do the repair.
4. Also tell them you want/need a hire car immediately and until the vehicle is returned fully repaired. You won't, of course, be paying any excess or any money at all.
5. If the injuries are relatively minor (small whiplash that will settle soon) then ask that they make an offer for damages. Tell them that if they don't and/or it's not enough then you will instruct lawyers. The savings they make on lawyers fees (both sides) will partly be passed to you. If the injuries are more serious (or potentially) then don't do it this way and just find an ambulance chasing lawyer.
6. Most insurers will bend over backwards in this situation as they know the alternative is for your insurers to instruct lawyers and fleece them. Mrs Peanut's BINI got smacked into a year or so ago and the other fella's insurers (Admiral i think) were brilliant. Repaired at my garage of choice with all genuine BMW parts, BINI Cooper S convertable (brand new) hire car, offer of compo on day 1 (later increased to a very tidy figure).
If you run into trouble PM me.