Get the key cut seperately from your existing, just incase the locks were ever changed, probably cheaper too. Then ring up all the accessible Renaults near you for the fob as I found each dealer varied in price, around £30+ difference between my closest 10. Once fob has arrived from France, its needs to be coded, normally only Renault iirc but have heard someone on here knows another place that will do. One Renault dealer actually didn't have the machine to code the key for my ph1! About half hour labour they'll charge, so again ring them all up as I found at least £30 per hour labour charge differences. Then don't be a muppet and walk over drains unless you have a tight grip on keys.
For reference, I paid £38 for coding after my dad had a moan I was a student and they could come down a bit lol and the fob for £77 from £85 as they couldn't code my key there and I kicked up a fuss for wasting my time going somewhere else. Was prob a couple of years ago but don't think prices have changed much on keys.