That's an older regimental kilt for the Gordon Highlanders. I know I've been told by Bob Martin that at one point regimental kilts were issued with no straps and buckles, and soldiers would add their own if desired (though I have no idea of the dating of that practice). So it could just be that the particular soldier in this case just didn't care to have one on the left hip. It's not strictly needed. If the kilt is worn snugly enough the inner apron won't go anywhere. Especially if a belt is worn. Of course if it bothers you a kiltmaker can always add one, or you can do yourself. You can also just add a button or even a small piece of (gasp!) velcro to the inside!

As to the waistband, the original in this kilt would have been green, as in this photo:


I suspect that it got worn out at some point and whomever owned the kilt either replaced it or covered it over with the white cloth. I would have chosen a darker color certainly.