Once it’s got its MOT, take it out on a long drive and get it hot. Bottle of Forte Diesel Treatment in the tank won’t go amiss either.
Generally people are very scared of Renaults (in fact anything French!) but probably the most reliable car I’ve ever owned was a Megane 1.9DCi. Personally prefer the older shape Scenics as they’re a less cumbersome shape, much more basic and easier to work on, and the 1.9DCi engine is a lot lazier than the 1.5 and still very economical. It’s mainly things like interior trim, boot release buttons and window regulators that die on Renaults in my experience, which is annoying, but relatively easily and cheaply fixed.
Oh and EGR valves cost a fraction of what they used to. Took it off my old Megane about 3 times to clean (needed it), but in fairness it was past its best anyway and the spring wasn’t returning the valve properly. Managed to get an OEM spec one brand new for £120 from a local specialist, which given that they usually last for 80-100k miles before giving any issues, seemed sensible to me.