I did see a very nice plain open wrap type thing that I am vaguely planning to make if I ever manage to get pregnant again here. Or what about something like this - not specifically maternity but would work with a bump. (Have assumed you're on ravelry, if not, def worth registering)
I'm not on Ravelry, but thank you both for the suggestion. I'm a terrible knitter (can only do scarves, hats and boat-necked baby jumpers) but was planning to send pattern & wool to my lovely godmother who knits like a dream.
There's a lovely book called "Natural Knits for Babies and Mums" which has a couple of maternity jumpers, a breastfeeding wrap and lots of nice baby things. All the patterns use organic yarn but you could sub anything that would work. Will try and find a link..