[quote 50ShadesOfCatholic]@TomPinch
Under section 70 they do have that power, absolutely.
What some of us are pointing out however is that it is discretionary.[/quote]
Do you mean this?
S 70 Health Act 1956
"For the purpose of preventing the outbreak or spread of any infectious disease, the medical officer of health may from time to time, if authorised to do so by the Minister or if a state of emergency has been declared under the Civil Defence Emergency Management Act 2002 or while an epidemic notice is in force,—
...
(f) require persons, places, buildings, ships, vehicles, aircraft, animals, or things to be isolated, quarantined, or disinfected as he thinks fit:
Which would suggest, as I think you do, the that D-G of Health can require any specific person to quarantine but there is no automatic requirement to quarantine.
There was a regulation mentioned upthread and I would have expected there to be one for something as particular as this.