Yes was planning to put gland on side of enclosure for the power lead to sit.Few things people are suggesting too;
Have some sort of cable strain relief for the cord coming into the box. Like a Pg8 wire gland or something.
Means if you accidentally pull the cord it will not pull the connections inside and also saves the metal box piecing the wires coating.
Yes planned the gland for the AC incomer. Will do on the earthing.Just commenting outside of the box, but if you want ease of replacement for the psu's it may be better to look at something in the way of changing the mounting of them to something such as din rail and din clips. It will allow easy termination access by simply clipping.
Also, without making me look like too much of a bigger dick than normal. Please Earth your enclosure and secure the AC incomer with either a gland or with strong cable ties and protection on the cable entry. Just doing my duty of care.