For whatever it's worth, I've managed to wear non issued boots through DP1 level courses in two different trades, and in two different operational units.
Your feet are important for what you are about to do. Bring non issued boots that work for you and maybe your staff will have some experience and apply common sense. As long as you have issued boots to fall back on what's the harm in trying?
Maybe try getting the new issued boots (not the zip ups though) as they at least look more comfortable but I'm sure they will still fall apart in the field. Your course isn't that long, you should be ok.