Hate to be pedantic but merely parking on the road has been shown in Plumbien v Vines (1996) is using therefore insurance is required.
Link
http://www.rjerrard.co.uk/law/cases/pumb.htm
the third party element is something else that the police and insurers are addressing following the one person who turned up 30 times to reclaim cars that had been seized because the PNC/Insurers data base showed they were not insured.
The owners paid the particular individual to go with his insurance that included third party cover to reclaim their vehicles.