I have a cooked breakfast now and not cereal as it's lower in carbs. Don't like eggs at all but have bacon, sausages and/or black pudding, and mushrooms. I have experimented and found that if I have two black pudding slices my carbs are around 20g and my BS reading jumps by 3, two hours after. So based upon this, as well as my experiment with baked beans, is this.
You're best having bacon, sausages, eggs, grilled tomatoes and mushrooms. I would still watch how much sausages you have due to their high saturated fat content, make sure you grill them until the fat drains - using the George Foreman does the trick for me.
I would restrict black puddings/haggis slices to just one slice as they are carby. Avoid baked beans (even the reduced sugar variety), fried bread, hash browns, and fried potatoes as they're high in carbs too.