FL,
Did the AAIB determine what the Client meant when he reported the Heliport "Open"? Did the Client know for a fact the weather was above Minimums for Operations at the Heliport or was it a blanket reference meaning only the "Opening Time" was at hand?
Likewise, when ATC told the Pilot the Heliport was "Open", did that tell the Pilot the Weather was satisfactory for VFR Operations into the Heliport?
How is Ceiling/Visibility measured at the Heliport and reported to Inbound Traffic?
Must Inbound Traffic remain clear of the Heliport until given permission to enter?
Is it ATC that issues that clearance or someone at the Heliport?