Sportsnut it's had to tell from your photo, but are the grip inserts in place?
They're short little metal tubes which fit inside the screw hole of the grip.
They prevent from tightening the screw too much and/or recoil impact.
One member fixed his cracked grips, with cyanoacrylate (CA) glue.
I research a bit and found wood pen crafters use it for finishing and strengthening their wood blanks.
I chose Starbond EM-02. Their claim was deep penetration, due to its viscosity just above water.
I finished my grips with 3 coats front and back sides.
You apply thin coats with your finger.
HINT: Use disposable nitrile gloves. I kind of found out after beginning, that body moisture on your fingers accelerates the CA curing process.