You have to eat more than 3 a day. I deally you need probably 6 a day, with three hour spaces. You won't meet caloric needs on 3 a day, unless you seriously eat pig sized portions at each meal.
Frosties are probably quite Sugary. I'd go for a good honest whole-grain over those.
The sandwhich sounded fine, but the Dinner would have been better without the Sausage Rolls. Should sub those for things like Turkey Skinless Chicken lean Beef, Pork, Soybeans, etc etc.
Having a sandwhich for snacks is a good idea, but you should perhaps be looking at other options too, nut just limiting yourself, and you need more Protein at Breakfast, like Chicken, Turkey, Lean Ham, Eggs, Peanuts, Low Fat Cheese etc etc.
If you choose Peanuts, go for Western Grown over Asian grown, if you're at all concerned about Asian ones, in relation to mould and Aflatoxins, as there is usually less issues with ones from say America, in terms of storage and production. Although I'm not saying all Asian grown Peanuts are a bad thing, but sometimes they can be.
If that doesn't really concern you then no worries.
I'd suggest for now making a few changes based on the above, and see where that gets you. You can always amend things in the coming days when needs be.