They lacked enough manpower to raid the house and still guard the perimeter. They didn't know if Sheila was holding everyone hostage and would shoot them if police entered or if she would shoot at them. They didn't know if she would run out another door or window on the other side of the house than they entered from. 9 officers ended up raiding the house with the rest guarding the perimeter. They didn't even have 9 armed officers initially.
They were using a megaphone to shout at the house. There was no tape recordings of anything.
When armed police raid a house,they're not to know if there are children present,or what kind of danger they could be in,so why was WHF any different ? If children are known to be inside the premises all the more reason to act as swiftly as possible. Lord knows there were enough police around the farmhouse.
I'm NOT taking your excuse about " lacking manpower ".