Birchy: Once fault is established by the insurance companies, the side at fault will rush to get you a replacement rental of equivalent class to yours (or sometimes better). They don't want to give the non-fault side's legal protection the chance to supply you with a car of their own at arse-rape weekly fees. It's the one good thing to come out of these legal cover sharks operating, blame is usually very quickly established.
When my 2 week old MK5 170TDI got clattered by a bus in 2007, my side's legal cover sorted me a billy-basic Golf 105TDI at the eye-watering daily rate of £93 cost to the bus company's insurance (although you did get Sat/Sun free if you had it for the week - how generous!
).
When my Scirocco got clattered, the other side were offering me a generous daily allowance at my local enterprise within 1/2 an hour of the incident. Enterprise insisted on spending every penny of the allowance by forcing me into a Merc ML350! Too bad it sat on the drive and did nowt when the whiplash kicked in hard.
Re the Road Hawk cam - giving it some serious thought, you can get a permanently wired lead to tap into the glovebox for £15. Some insurance companies may decide there's more risk of someone breaking into your car to pinch it than it recording a non-fault event and absolving you in a claim. I suppose it depends on your insurer. Perhaps they'd be happy for you to have one on the assumption that you don't leave it on view in the car when it is unattended (in much the same way as a portable sat-nav left in the car could be viewed by an insurance company).