Sevenoaks,

Once you have a second one of those kilts in hand and once you have gotten some value from the first one ( in case this next part ruins it) why not try a little jackleg tailoring? Get the biggest, sharpest scissors you can lay your hands on and get a yard or two of binding tape, such as you would see on the edge of a blanket. Then carefully chop an inch or two off the top of your kilt, sawing your way through every thing at once. You will probably have to rejigger the strap and you may find it rough going to sew the binding tape on, but you should be able to cut off some of the high waist to end up with a hip-height kilt. If you are so inclined, you may want to try trimming and flattening the new waist before binding it- or you could even resew the original waistband, if there is one.

If you have never done anything like this, you may want an "adult" present while you are at work- someone who can warn you when you are about to do something completely ruinous. But remember, you bought it. It is yours to do with as you will. And, while somebody may have had better tools, somebody made it in the first place. Given time and patience, you can do what they did, only shorter...