I found nursing tops in H&M - only one basic style and a very limited range of colours, but 13 quid each, I bought a couple at 20 weeks and am hoping they will fit ok over BF boobs! (They were short-sleeved, I was in there in July, we don't have a store particularly local to us. Think a 2-pk of black and white was 20 quid, but I think white tops are a bit of a false economy.)
I didn't get any proper BF tops last time round, I lived in baggy T-shirts from Next, at least 3 of us at the same baby group had the same one but there were never more than 2 of us there in it at the same time!