What is 'good' or 'bad' depends entirely on your perspective about food and nutrition. As someone who is a long-term, 'lifer' low carber, this is what I would say:
Breakfast: sometimes nothing, sometimes a pack of malteasers.
Dreadful. You need to be eating something to help stabilise your blood sugars. The worst possible thing you could be eating is sugar. Incidentally, this also includes cereals, bread and fruit juice. Best choices for breakfast are protein and fat - bacon and eggs are a perfect choice. Otherwise, boiled eggs, scrambled eggs, full fat yoghurt
Lunch: egg and bacon sandwich, crisps, chocolate bar, apple juice and sometimes sweets
Way too many carbs here. The only thing that does have carbs is the egg and bacon. Try eating something like protein plus salad, with an oily dressing on it.
Tea: takeaway or cheesy oven chips, sometimes beans on toast or pasta
A massive carb overload.
Again, base your meal around protein and fat, with carbs in the form of vegetables (not potatoes) and salad, with an oily dressing.
Is this diet going to make me grossly overweight with time?
Yes. But more worryingly, this will set you up for a later life with a high risk of diabetes, hypertension, cancer and/or Alzheimers.
Cut right back on the carbs. Make sure that your carbs are coming from veg and salad, and make sure that you eat more protein and fat. Don't be afraid of fat - fat is good, if you're eating low carb.