Ive read this morning over on CYC forum a recent change in legislation regarding number plates and displaying flags.http://www.direct.gov.uk/prod_consum_dg/groups/dg_digitalassets/@dg/@en/@motor/documents/digitalasset/dg_067666.pdf
If you have a flag on your plate you need to have the country identifying letters displayed as well...from what I can tell. Just thought it would be useful information for you bud