It depends on what you are eating. If I go to bed hungry I can't sleep. The only thing to do is plan a variety of snacks that you like before bed and test in the morning. Depending on your sugar levels you will then be able to plan evening snacks.
Whole meal bread is better than white bread, so you may only have to make slight adjustments, and it may even help you sleep better too.
Ask why you were told not to eat after 8.30. On w Wieght Watchers diet (not specifically for diabetics) the advice was to leave at least two hours between eating and going to bed as it gave food time to go down and prvevntd things like indigestion and heart burn, but I am not sure how good this advice is or if it is just a slimming myth.