What's the climb rate of the Dash? 20 mins into the flight would indicated a "high" bird and probably quite big to destroy the spinner. What's the sector time GUR(?)-BHX? Be interested to know exactly where the strike occurred.
The report suggests strike was on departure from GCI with impact damage to prop spinner rather than blades or by ingestion. Reported to flight deck by cabin crew.
Shutdown only after one of one of pilots had gone back and viewed damage. While there was some vibration (or even more than usual in a Q400 according to some wags) engine was functioning normally and could presumably have been re-started.