As nice as it is, I personally think it is priced way above what it should be for a private sale. The only hint I can see it being blue is photo 11, however it does look black in all the other pics.
I wouldn't be paying anymore than £25k personally IF I was going to spend that much on a C class in the first instance. At that price point I would be looking at the E/CLS variants. Yes they are different animals but a different level of quality and refinement too.
All said and done, if it is what you want and ticks your boxes, that is all that counts. Do whats best for you and your circumstances.