I read the www.telegraph.co.uk and the U.K. magazine CAR and I ask genuinely are you sure the C-class is cheaper there?
They do sell smaller engined versions of the C plus cloth seating and non-airconditioning versions are popular (well lately you find more A/C ) but optioned out C-class models are probably the most expensive car in their class on the island. Tires, fuel and oil are more expensive than the U.S. where the cost of living is usually cheapest in the industrialized west.
And there is a hugh uproar about the service provided by MB dealers in the U.K.

If your working for a company that provides a rep car things may be different ( did yoy know new cars are taxed also on CO2 emission? )

You can always buy a Perodua Kelisa for 5200 pounds