tipex -
I feel a lot of sympathy for you and everyone else here who is not able to get enough rest. I didn't sleep properly for an entire year either, DS was up very often for the first 10 months and it looked like he needed me around all the time.
If it's any comfort though, I really do think it depends on the baby/child and sleeping arrangments rather than the feeding method. I have asked so many people about this (in my insomnia days) and they all seem to say that what a baby has in his stomach and whether he is a good sleeper or not have no connection.
If any thing formula can cause constipation, upset tummies, and all sorts of other things which will wake a baby up as often or more often than bm which is wonderfully good for the tummy 
I thought DS would sleep better once he was on solids past 6 months, but he didn't. So that was a myth out of the way 
I know it's really tough, and I hate to be an advocate of it as I am very much an attachment parenting sort, but have any of you tried a gentle method of cc ? I did this with DS when he was 10 months old (I would not have done it sooner) and it worked for us. I started putting him into bed when he was still awake (after his last boob feed) and he would cry of course, but he was only upset for 3 nights and that was that. He cried 16 mins, the 1st night, 16 mins. the 2nd night and only 5 mins. the third night, he was then fast asleep. I checked on him every 3 - 4 mins in the interval, I never let him cry without checking on him. I would stroke his face and speak loveingly to him, but would not pick up. He got used to it after a few days. I know I am probably very lucky, but it might be worth a try if you haven't tried it before.
Even now at 21 months, we put him in his cot at 8:00 pm every night, he doesn't sleep until around 9:30 - 10:00 but he will play with his toys and books until he falls asleep. We very rarely have to go in because he is upset. If he cries its usually due to teeth and of course we always go to him immediatley when he is not well and I bf.
The one thing I have noticed though is that co-sleeping although a wonderful thing, past the first few months makes it more difficult to stop bf in the middle of the night. Our DS was in his own cot in my room by 3 months, so has no memory of sleeping in my bed, which I think has made it easier. If he needed a bf, which of course he always did as a baby, I would bf him lying down until he fell asleep and put him straight back into his cot. This would sometimes happen as often as 6 - 8 times per night, but he would always end up in his own cot.
It was by chance mind you, because I have suffered from severe insomnia since I was a teenager, so was never ever able to sleep next to DS in the same bed, although I would have loved to.
I think older babies and toddlers do get into the habit that if you are very very close by and they can smell you and feel you they will wake up out of habit.
I wish you all better sleep in the near future !