Apparently the speed units are in compliance with a recent decision.
Victory for Britain's metric martyrs as Eurocrats give up the fight
A directive published today will be put to the Council of Ministers to be approved by EU member states within the next few months.
It will confirm the UK's right to carry on using non-metric measures such as the pint, the mile, and pounds and ounces.
W00t! thanks for the info and the link.