It is 6 "clear" days - ie 8 days stand still - I ended up with a DEFRA audit last year after they advised me I was ok to move animals - thankfully they had the conversation recorded to their fault.
The exact wording is as follows:
Any movement of livestock onto a holding imposes a standstill period - either 6 or 20 clear days (not including the day of movement on or off).
Moving sheep, goats, cattle onton a holding will trigger a six day standstill on sheep, goats, cattle and pigs.
Moving pigs onto a holding will trigger a 20 day standstill on pigs and a 6 day standstill on sheep, goats and cattle.
Exemptions:
Movement direct to slaughter
Movement to slaughter collection centre
Movement to dedicated slaughter market
Movement to shows or breeding animals using an approved isolation facility.
CLEAR AS MUD!