i am with chas on this. you cant correct improper sewing. the fact that your tartans pattern is not lining up was do to it not being in the right place at the time it was fixed when they stitched the fell.l the best you can do is give it a nice press and ware it.
i know we cant all spend 1000.00$ for a new kilt this is why i make my own. i am a vary experienced tailor with 30 years of sewings mens suiting so a kilt doesn't present much of a problem ones i learned how to do it. if you decide to do one your self Get Barbra T book its vary exacting in its technical out line of the proper making of a kilt. even if you are not a superb tailor you should if you faithfully fallow the directions get a better kilt then what you have now. at least your tartans lines will match. you can ware a lot of just OK kilts and get away with it but as far as I'm concerned if the lines don't match theirs no way to cover that up. but on the other hand a kilt is a kilt ware what you have and be happy its still a nice color hope that doesn't come off sounding hady of proud as thats not the way i meant it I'm just trying to be practical
Paul