Dior Rose Gold Sunglasses Dupe

How beautiful are these Sunglasses ?! All the blogger gals are jumping on those Dior sunnies, but hey I'm a student and as much as I want them, they cost over a months rent, so I decided to go on a hunt for some dupes. I found these on eBay for £10.45 and although you can definitely tell they're a bit cheaper and aren't identical, they still claim to have UV Protection and still look beautiful. 
If anyone has any tips on how to keep these mirrored babies unscratched sand clean then please holla at me because they get so grubby!