Do you have lactose free dairy products available where you live? Here we can get everything without lactose, so even those with lactose intolerance can eat dairy.. If you can't find it, and don't want to eat regular yoghurt, just substitute it in the following recipe with orange juice, that's what my mom would do (she's allergic to milk protein, and can't have any dairy at all, but that's a very rare condition, fortunately).
Breakfast suggestion:
1 Banana (200 g) contains 56 cal/100g 112
1,5 dl natural yoghurt (150 g) 57 cal/100g 85,5
1 dl All Bran bran flakes (30 g) 326 cal/100g 97,8
together they make 295,3 cals
If you're eating about 1200-1500 cals a day this makes about one fourth of your daily energy, which (at least where I live) is the recommendation. And I assure you this keeps you going till lunch. The banana will give you energy immediately and the yoghurt and bran flakes will keep it up for a long time.
The yoghurt is un of the unflavoured, unsweetened variety, containing max 1,5% fat. I hope it's available in the UK as well. You can mix it all together, it's fast to fix and crunchy to eat. If you want variety, you can do this with apples instead of a banana, two small ones or one big one. That will drop the total calories down to about 250.
Tell me, what you think, so if this is not to your taste, I'll think of something else.
Juliette