In San Francisco at present and may see about hiring a car from Hertz for a few days to go to Yosemite, Lake Tahoe etc. How exactly do I get the miles? Looked at the Virgin website and it mentions some sort of number but I've really no idea what it's talking about.
You need to use the VAA CDP (Corporate Discount Plan) number which is 708870. When you book (if online) there is a field in which to place the code, if by phone advise the operator.
After the hire keep all the relevant documentation, you will probably have to chase FC for the miles (1000) and will need supporting evidence.
Good luck.