...start-up clearance is required from Oban Info...
Where's the problem?
The Islander flights are commercial and passengers may be being marched out to their flight while somebody else starts up their people mincer next to them.
Or a heli parked into wind and facing away/ unsighted from from another helicopter in the final stages of rotor shutdown, might hit the start button and cause damage to the heli behind.
Sounds like sound risk management.