We have the exact same problem on our 2007 1.2 Clio Ripcurl edition, which has the same 3 dial heater controls.
Doing google searches it seems that the heater resistor bank, behind the glovebox, is a common problem but from posts I've seen it usually just leaves setting 4 working which doesn't go through the pack. Like yours ours works on 3 and 4 so I don't know if this is the same problem.
Someone on eBay will fix the pack for about £20 but they say the connection can come loose so to try wiggle that while heater is on setting 2 to see if it works. I am hoping it is this because ours stopped working on 2 for a few days, then started working for a few weeks again on its own and then stopped again yesterday.
A new pack from our local motorfactors if it needs replacing is just over £50 or £90 from Renault plus another £80 to fit.