My 2p from recent experience..
5 owner. 18k miles. 80-90% service history. I'd of thought starting with a 7 - possibly 75k will snap it up quickly
These cars are moving up in value - FACT. They are becoming very safe cars - it's virtually a given (at worst case scenario) you can buy, use, and not lose a penny. At best - after expenses - still get a return on your money. I think (and from talking to a few people-in-the-know recently) that CSL's values will increase somewhere between 10-15% over the next 12-18 months.
If in rush to sell chance it at 79k - I don't think you'll get many bites or nibbles over this.
GLWS