Hi Roy. Good idea!!
I was thinking of getting my cambelt, waterpump and aux belt done through RenTech down in Portsmouth and let them fit it using their parts but I may do what you say Roy and purchase all the above parts from Karl (Genuine Renault parts) and ask RenTech to fit them. They may not but I can only ask. It will cut down on the overall price as I was quoted total of £540 incl labour and VAT by RenTech if I went through them.