
so I have decided to do it proper way

Here I am using a wiggler to position the hole exactly half way between (it's 0.4mm in one half and 0.4mm in the other):

Checking with centre drill (last chance to correct):

0.8mm dia 5mm deep:

I have spent some time sorting out a quill on my milling machine (it was stiff) - my fault, caused by overtightening the four bolts holding mill head.
When correctly torqued to 50 lbs/ft it has recovered and quill is now smooth and light

End result is quite acceptable

