How much does is cost to maintain a Bently Continental?

That's one lovely car, friend, you do have taste. As I am unsure as to where you live, let me keep it general:

This vehicle will give you the fuel economy of approximately 2.5 regular, stately saloons - which means, your fuel bill will be about 2.5 times as high as it would be with, say, a Mercedes E320 or a Holden Commodore or a Cadillac STS. If you need to go in for maintenance, better not be squeamish, it can hurt. A set of shock absorbers is listed around US$ 4.000 installed - let alone difficult things.

These cars last forever, provided you treat them with due respect. This may mean investing about 5 to 10k US$ in maintenance annually, plus the fuel I've mentioned, and other things (insurance is sadly ridiculously high for these, you could ensure 10 Porsches for the same money in some countries).

I would buy slightly used to take the edge off the depreciation curve (at a price of $300.000, this could easily be 100k down), unless you have enough revenue to offset the depreciation against.

Would it not be proper to ask at a Bentley dealership? How come you could not spell the name of the brand correctly? This is a highly suspect posting.

Well congratulations. One day I hope I'm in the position to answer your question. Good luck.

You don't want to know.