Hi Andy, you certainly seem to have had your fair share of bad luck with this one. I would say that your experience is not typical of most Renault owners, otherwise I doubt if they would still be in business!
However, some of your 'bad luck' is certainly not exclusive to Renault owners. Rattles from dash and trim are commonplace in a lot of modern cars. My Passat rattles like a
. I know I can take it in to get sorted under warranty and I really should! I personally think that it is due to all the 'carbon fibre-ish' and 'faux-aluminium / wood' inserts that seem to adorn the dashboards of today. The more 'bits' you put on, the more there is to rattle. My 1990 Cavalier had a very simple dash with only a small splattering of 'wood-like' bits and never made a noise.
Also you mention that the front discs and pads were replaced due to excessive wear. Did Renault agree and do the work under warranty? What was the mileage? Our Scenic had pads all round and front discs at 36k. My last Passat had the same at 40k. One of my guys has just had the same on his Passat...wait for it....42k. I suspect that it is just that manufacturers are developing brakes with better braking efficiency, at the cost of shorter life (softer materials). Interestingly though, my Passat has 45k and still plenty of wear left
Have you asked Renault for a quote to extend the warranty? It will probably be quite reasonable and will give you that extra piece of mind.
Good luck with it mate!