Boot/Tailgate adjustment

Does anyone know how to adjust a boot alignment for a 3dr tintop, am asking as looked at it the other day and is higher over the rear lights on the left, maybe a good reason why I'm getting water in the boot. Is it just the case of undoing the 4 bolts on roof under roof lining, there seems to be a sealant under the hinges, I assume this needs replacing once the adjustment has been done.