Hmmmm this depends on whether you would particularly like it written off or not. Your options are...
Leave it to your insurance approved repairer to fix. With this option you'll get a very small courtesy car and your car will probably be repaired with you having no knowledge of the cost. However IMHO the repair quality will be poor, but it will be reasonably hassle-free.
Go to local bodyshops and get quotes. I'd guess the price of the lens to be under £100, tailgate around £500 (I may be wildly out tho), paint & labour £500. So a total of somewhere between £500 - £1500. Most repairers will also give you a small courtesy car.
Demand that the car is repaired by an authorised Renault dealer with genuine parts. I think you'd still need quotes so would probably need to visit a few with the associated inconvenience. Obviously this would be the most expensive choice.
Additionally (assuming you were not at fault in the accident) you have the right to a comparable car while yours is being repaired. You would be quite within your rights to go and hire a 1.9
diesel estate (or similar) at your own expense, and eventually get the cash back from the insurance company (could be a year or so tho). You are also entitled to any out of pocket expenses you have like fuel reciepts for the body shop visits etc.
Another option to consider is to provide quotes for Renault to do the work, which will possibly be too high for them to repair and therefore they'll write it off paying you the full market value. Then buy the car back as salvage from your insurance company for a few hundred quid and get used parts from a breaker and get someone to repair for another couple of hundred quid. With this option you keep your car (as a Cat D write off) and have more than a grand in your pocket.