Thanks Lads
I think my shop Gremlins have got that little spanner now Chris I wish a new what the little buggers are building.
A good mornings work done. drilling and tapping for the inlet and exhausts ports.
When starting on a new feature I like to mark the first one out, then with a bit of calculation work out the coordinates for the DRO, coming at it in two different ways gives you a check that you've got the features in the correct position.

Another thing that can go wrong when your doing multiple parts is that you end up loading the work the wrong way, so it helps to mark the end/side your working on and to store them in the box all the same way.

With everything correct it was just a matter of spotting with a centre drill turning the job round to do the other side etc etc then swapping over to the drill to depth repeat repeat next hole position repeat repeat.
To get the depth correct I used the DRO on the mill.

Then over onto the tapping stand to tap M2:- John put me onto a cheap supply of HSS taps but I'd already bought a set of carbon taps so I decided to use these to get the use out of them, these taps are good quality UK manufacture, It always pays to use good sharp taps as bluntness is one of the main causes of a broken tap.
Her we are a very satisfying morning work.

And an introduction to another brush this time an old toothbrush the stiff bristles are just the ticket for clearing the swarf from the tap, clogged taps are another cause of breakages.
Cheers
Stew