Renault Clio II - Renault Clio keeps cutting out when slowing down/ - peachesandcreams

I have a T reg Renault Clio which keeps cutting out when I get to traffic lights and roundabout etc. sometime won’t start straight after and have to sit on side of road! I have just paid for new fan belt and cam belt and car still unreliable. Its Real pain and dangerous as it keep happening please help.