You don't need to do that.

I've done the same thing, all you need to do is remove the cubbyhole on top of the dash, remove the blanking plate and attach the cupholder with the two screws. The remaining screw is difficult to get to, and unnecessary anyway - I've had supersize McD drinks in there with no problem!!

Inbetween bending the needle on Aroads and winging it round roundabouts I have to drag myself up and down the country on motorways. As a man who runs his own business, waiting for a cup of super heated (how do they do it?) motorway coffee to cool is an expensive business. Therefore I must pose a question more suited to the Renault Megane forum. I have bought a cup holder for my 98 turbo via dealer (it standard on lesser models). I have popped out the blanking plate in the upper dash next to the hazard switch but will have to pull forward the lower console (the bit with the heater controls and radio in it) to fit the lower locating screw. How is this section loosened enough to put it in? Please save the the cost of a Haynes Manual as nothing ever goes wrong with it!!