The simplest fix is to:
1. Remove the old wedge completely.
2. Drill out the existing holes in the plane (through the sides).
3. Fit a steel rod.
4. Drill out a block of wood a little over the size of the wedge and turn it to
round. Insert the steel rod through the centre.
5. Now shape the block to the dimensions of the original wedge. Remember that
the rod will be offset.
6. Remove the rod, insert the wedge in the plane, thread the rod through the
body into the wedge and again the body.
7. Trim the rod to size. Bob's your aunty.
There is a built on my website. This includes a shaping of the wedge.
Regards from Perth