The helicopter was refuelled from a drum positioned approximately one metre from the left hand side of the aircraft. The helicopter was parked facing north with an approximate 15 knot wind from the east. Pilot and passenger then boarded the helicopter and commenced normal start procedures before lifting into the hover. The helicopter was close to maximum all up weight. After coming into the hover the helicopter was weather cocking and difficult to stabilise. Due to the proximity of the fuel drum, out of sight on the left side of the aircraft, and the aircraft weather cocking in the cross wind, the pilot decided to do a hovering left hand circuit of the fuel drum to enter into wind. As the pilot looked to his right to check the area was clear the aircraft yawed to the right. The pilot pushed full left pedal and applied left cyclic to stop the yaw at the same time pushing forward cyclic to clear the drum. The rear of the left hand skid came into contact with the fuel drum and the helicopter rolled onto its left-hand side.