As per UKC:
Climb Houdini without the detached block on the left hand side of the cave, climbing into the pockets on Ian’s roof is out.
Start as for Houdini, climb diagonally through the roof using thin crimps/flakes to gain the good hold on the left side of the roof. Gain the crimp on the lip of the roof, then to the pocket. Finish up the arête as for Houdini.