Gutted for you mate cos it's a sad day when people would sooner risk breaking in to a car to release and remove a bonet rather than go to a breakers yard and pay £10-25 for one. Clio 16v/Williams items are getting harder to source though now where as once there were loads in breakers yards cos I've been forced to turn to Renault for loads of bits recently. Thankfully my cars are garaged at the back of the house and the car and the entrance is belled up but that doesn't mean it's not vunerable and I'm not looking forwards to the day when I find someone's tried to get in (and i'm sure it'll happen somewhere down the line) cos they thieving scroats are brasin as hell and will still try if they *think* (I use the term loosely) they can get in and have a brief look-see.
I've heard some bikers have their pricey frames, moulded/comp panels and other bits like seats injection "chipped" for anti-theft purposes and it's a system recognised by the UK insurers to but it ain't cheap. Furthermore, I'm not sure what companies actually do the work either but would you want your doors, boot, bonet and otehr bits doing? If so, maybe a group buy between all the clubs would be a good solution for those serious about protecting their cars would be a better idea than using magic markers.
Mink