If a helicopter crashes, they are normally grounded.
I would say that historically, this is not the case. An aircraft with 20+ years of flying experience would not normally be grounded following an accident, unless there was some clear mechanical cause. The Super Puma family has been running since the early 80's and has an excellent safety record, so the decision to ground would appear to be more of an Oil Company decision rather than airworthiness or safety related. I guess that explains the stance from the AAIB and CAA who have not issued any grounding of the aircraft in response to these sad events.