Thank you everyone for your replies!

Right to start with then I am going to draw it out on inventor to get a better idea of the layout

Main points to consider then:

1. Steel or aluminium cover. (whatever my workplace has available)
2. Hinged lid, with an earth point to connect it to the main case
3. Raised steel platform for mounting the components onto. This is then earthed to casing.
4. Star grounded earth setup, maybe a bus bar to make earthing easier, which is then connecting to casing earth point
5. Additional space for upgrading.
6. Cooling fan and filter setup. 2 intakes/1 exit
7. Suitable mounting holes for attaching to wall etc.

Anything else?

One other question, I'm yet to get my WC spindle. Does VFD need to be mounted inside the enclosure as well then?