BAe 146 & DH8 - Flap retraction is based on speed, usually V2+10 for the flap setting that you have. If going around from the landing configuration, it is usual to retract to F24 (146) or F15 (DH8) then in increments as speed increases until Vfto (146) or Vfri (DH8).
The only exception I can think of to this, is a windshear encounter, where the current policy is not to reconfigure until in no longer affected by the shear.