Red Bellied Black Snake

We found this critter trying to get into the greenhouse when we went to water this afternoon. 
It was big, at least 2 metres long and fat, but quite docile and waited around while I got my camera for a shot. But then I blinked and it was gone. We couldn't figure out where as there was quite a bit of clear lawn between it and and the bush. Maybe it found a spot to hide along the edges of the greenhouse but we couldn't dislodge it with a bit of careful poking. 
No doubt it will return and I've put some wire and netting along the greenhouse to trap it in case it is in there and tries to get out.
I don't mind snakes. They are rather magnificent creatures but I don't like having them around with young children due to visit.
Red  bellied black snakes are venomous but there are no recorded deaths from their bites. However we know from experience they are lethal to dogs and no doubt could be to children.