I think it would probably be too greasy then, not to mention it'd taste kinda weird.
Perhaps coating them in melted sucrose could work. I've done that with popcorn before, so perhaps the same concept could be applied to Huel bars. If the amount of sucrose used was less than required to stop the bar from crumbling, then it'd result in less total sugar being used.
EDIT: I have an idea ... melt the sucrose in a frying pan. Freeze the crumbly bars in the freezer so that they hold together. Then hold the frozen bar with tongs and dunk it into the sucrose. The bar would get a light coating of sucrose, hopefully enough to keep the bar solid, but not enough to massively effect the nutrition of the bar. Hold the bar with the tongs until the sucrose has solidified, then leave it on a rack to cool down.
So long as the bar isn't left in the pan too long, it shouldn't burn (pop corn doesn't).