I did buy a breastfeeding dress and 2 tops from jojo - however, found them to be quite huge - and having been fed up wearing huge maternity wear, and having lost a reasonable amount of birth weight quite quickly - I opted mostly for sticking to nice teeshirts, with a cardi, so that I could discreetly lift my top in public places, with the added "security" of the cardi, or overshirt to wrap around me and the baby (so noone could see my wobbly bits from the side or back!!) - noone ever noticed I was breastfeeding in public, and I did it everywhere, including Cost coffee, old ladies tea rooms, park benches etc!!!
Having spent money on maternity wear which I wouldn't wear again (for a while!!) I resented to continue buying "specialist" clothes, and was pleased to start wearing my old clothes again (even if they were, and still are a bit on the tight side!!) and felt that if I bought new (bigger clothes) I could at least still wear them when I stopped breastfeeding rather than adding them to the maternity collection.
Another reason was that I couldn't afford to buy tonnes of breastfeeding tops, and again got bored with wearing the same two teeshirts and one dress over and over again!
I never found anyone else who sold breastfeeding tops, but that's not to say there arn't any others?!