This may have come up before, but with the recent hike in the Congestion Charge thought it might be of interest.
"Central London Congestion Charging - XXXXXXX / NM
Thank you for your recent enquiry, received on the 5th July 2005 regarding the 9 + seater discount of the Congestion Charge .
Please be advised that as long as the V 5 / V 5 C document shows your vehicle as being a 9 or more seater you can apply for the 100 % discount by completing and returning the relevant application form, which you can request from our Call Centre on the number below .
I hope this clarifies your query .
If you have any questions, please contact us on 0845 900 1234 ( or Minicom number 020 7649 9123 ) or visit our website
www.cclondon.com. "
I don't drive in to London, but for anyone who does, if you have a LWB get your V5 changed to show it's a 10 seater. The exemption is valid for a year.