Its hard to say, where is your left hand?
To get to the flake, with my right hand on the arete and left hand in the roof pocket, I have to heel hook on the front face of the block with my right foot, put my left toe into the roof crack, right foot moves to press off the front face then go to the flake. I have some photos to put on that may help.
Glad someone is giving it ago, let me know how you get on.
Cheers
Lee