It's hard because you don't know if they knew the things they were doing upset you and didn't care, which would be abusive, or if they honestly didn't realise, in which case it suggests they were good parents who tried their best but, like everyone, didn't get everything right.
Do you know what their childhood were like? Because if they had issues with bad memories from their own parents when they grew up perhaps they were consciously trying to do the opposite with you and went too far? For example their parents never helped them with/valued doing homework, so they didn't do well at school and didn't get great jobs, and then as adults felt frustrated with the way they could have done so much more, so focused really hard on making sure you and your brother didn't make the same mistake, and got frustrated if you didn't understand why they were making such a big deal out of it.
Do they have good social skills themselves and value interactions with others, or do they prefer to keep themselves to themselves?
Some of the things you mention could simply you attributing the same feelings and knowledge you have automatically to them - to you it seemed obvious that your clothes were obviously 'wrong' and made you a target for bullying, but some people genuinely aren't bothered about clothes, and wouldn't be able to really 'see' the difference between a long shapeless grey skirt and a short, stylish one. To them they would both be grey skirts and it would be pointless spending a few quid more on the second. They certainly wouldn't be able to make a correlation between skirt a = people mocking you, skirt b - people liking you.
The photo thing seems similar - I would suggest that it never entered your dads head that taking the photos bothered you in anyway.
Things like Sunday school I can't see as a huge issue - you say the people in charge were 'mad' but unless they were actually abusive it's not really a huge issue to be forced to go somewhere you'd prefer not to as a child. I understand you'd rather have been somewhere else, but lots of children would probably prefer to not go to school/a childminders/visit great-grandma but have to! Perhaps Sunday school was the only time your parents could get some time just to themselves all week?
On the other hand, you and your brother both making suicide attempts at similar ages is something that is unusual.
You say you don't want counselling, but has it helped writing it all down here at all? perhaps you could just write down things as and when you remember them in a journal/blog, just to process your feelings about them. You could try writing it down and then burning it to forget about it and move on, or perhaps keeping it and then referring back to it when you do something you regret with your own kids, which might help you make sense of it, e.g. 'God I really regret shouting at DD now but she was being so rude I couldn't help it, she really knows how to push my buttons and I had such a rough day at work - hmm perhaps that's how dad felt when he hit the table when I was doing my homework.'
Or, on the other hand you might think, 'God DD was really winding me up then and I understand why I shouted at her, but I can't imagine ever screaming in her face like Dad did to me, that probably was wrong.'
It might allow you to process it a little bit?