'Section 2.7.3 of the operator’s Operations Manual Part B (OMB) stated that the autopilot should not normally be engaged below 1,000 ft (the minimum engagement height is 500 ft agl). The operator confirmed that, when departing from Stapleford, even in IMC, the autopilot would typically be engaged after the aircraft had turned towards its first navigation waypoint (in this case, Brookman’s Park VOR) at which point the aircraft would be at about 1,700 ft amsl.'
and also from the report
'If he believed the autopilot to be engaged when it was not, he would have noticed his error when he commanded the turn and the heading remained constant. Given that the operator expected the departure to be flown manually, it was concluded that the autopilot was probably not engaged.'