Astonishing to report, but Mr Sproul has got the law wrong. The Vehicle Excise and Registration Act 1994 applies to Scotland. Using or keeping an unregistered vehicle is a criminal offence across the whole of the UK.Sproul says that VED is decriminalised in Scotland, but I can't immediately find anything to suggest this is the case.
See https://www.legislation.gov.uk/ukpga/1994/22/contents