Mike Barnes  gurgled happily, sounding much
like they were saying:

>>Mr Herron - who led the campaign to stop the prosecution of British
>>shopkeepers still using imperial measurements -

> ISTR that the campaign was actually to stop the prosecution of British
> shopkeepers who refused to use metric measurements.

Exactly. It's not illegal to use imperial units - only to NOT use metric 
ones. Dual-unit scales are perfectly legal, even set to imperial units.