They are M8 holes, slotted sideways a bit. The CAD drawing is a bit cluttered an OTT.
THe important dimensions are the M10 holes are 64mm apart, and the top holes are 100mm above the M10 holes.
The M10 holes are very loose (drilled to 12mm), and the top holes slotted sideways to take into account any errors in my backwards engineering (making a paper template from bits of string, rulers, and card
)