You only fill out section 11 - V5c/4 - if you are personally exporting the vehicle for more than 12 months.
It says this clearly on the back of section 11
see here on pg 8 http://www.direct.gov.uk/prod_consum_dg/groups/dg_digitalassets/@dg/@en/@motor/documents/digitalasset/dg_065264.pdf
It says if you are exporting for less than twelve months or selling privately to someone who does not have a Great Britain address....
"You should fill in sections 6 and 10 with the new keeper’s name and address. Both you and the new keeper (buyer) must sign and date the declaration in section 8. Give the whole V5C to the new keeper to aid registration abroad.
You should then send a signed letter to DVLA, Swansea, SA99 1AG giving
the vehicle’s registration number, the make and model of the vehicle, the
date of sale or transfer, and the name and address of the new keeper.
Once we know about the change of keeper, you should receive an acknowledgement letter to confirm that you are no longer responsible for
the vehicle. If you do not receive the letter within 4 weeks, please phone
0300 790 6802. "