Hi Adam.
I have worked on far worse brakes from what I can see in your photograph. It would be a very good Idea to remove the pressure by removing the trigger guard screws so the broken ends dont rub together under pressure removing the end of wood splinters. You are lucky that the chequering is in good order and that will hide the majority of the break line. Usually the repair would consist of two dowels positionedeither side of the top strap to trigger plate screw some repairers use brass stainless steel or fibreglass dowels and a top quality epoxy resin adhesive. The photographs are of a splinter forend that split into two halfs end to end the break line is at the point of the arrows, I doweled and glued it about twenty years ago and the gun is in continuous use the line is noticeable when pointed out but in normal circumstances it is invisible. So your problem is not all gloom and doom
Good luck with your problem
Damascus
