I found all the maternity/ breastfeeding clothes from last time this weekend, I had bought 2 primark breastfeeding nighties which turn into peephole nighties after about 30 seconds of wear! Not sure if its bad design or just my huge norks overwhelming it! 
By far the best I found was some primark dresses made of lightweight jersey fabric, they do sleeved and strappy versions, I went for the biggest size I could then just popped a cardi over the top( although last time I was still fully dressed and had to wrestle my trousers off mid contraction!)