for the steering column or rack alone in the price of parts, you're looking at a good 300-350 pounds and if it's the steering rack you're looking at around 4 hours labour and 2-3 hours for the column. if you get this done at a renault dealership, that's 350 + (4x80).
my advice would be to go to a trusted local independant garage, and have their verdict. again as liam says it could be something as simple as needing greased or a loose retainer nut. this also isn't a specialist job, so unless you are still in warranty then i wouldn't recommend that you go down the renault route althought the part will have to be sourced through renault unfortunately!