As the law stands mate you do not.....but it's a good idea that you do otherwise you could lose a good few hours hunting if ARU show up trying to explain yourself
On another note...lets say i turned up at one of my perms at 3 am and land owners were in bed....i was busy doing my thing and plod turned up,,,,and had to wake up the said land owners because i failed to notify the police what i was doing....i doubt they would be very happy....ok this could happen anyway but it's less likely if i had informed them first