The place I always look for parking (and hotel/parking combinations) is
http://www.holidayextras.co.uk
For example, 7 days parking with CPS (Chauffeured Parking Service) who pick up your car at the terminal and drop it off when you return is only £82.80 (at Heathrow, at the end of November - since I am doing a trip then).
I also looked at BA's parking service for that period (we will be travelling Club World), but it was about twice the price (£144.95) - eeek! Look at
http://www.britishairways.com/travel...public/en_gb#6 Ok, an extra 60 odd pounds isn't a lot compared to two CW tickets, but...
We quite often use CPS (through Holiday Extras) because it is not very much for expensive than standard on-site airport parking (Purple Elephant - pre-paty through Holiday Extras - £55.60 for the 7 days). It saves time and is particularly worth it if you have a lot of luggage (i.e. you are going skiing).
Boo