I never liked the cocking handle on the Bren Mk II -- especially on my Len Savage SA Bren which uses a massive spring. The Bren Gun Saga discusses a solution that involved modifying the Mk II receiver (removing the "hump") and brazing a new piece into the receiver so the standard Mk I handle would fit and lock when folded forward. Not going that route with my Mk II, I modified a Mk I cocking handle slide (plugged, relocated, and redrilled the hole) and the Mk I handle (very slightly shortened) to clear the "hump" on the Mk II receiver. Here's a pic. It locks forward when folded and works well.