Didn't think you could get underwired nursing/maternity as it's supposed to affect your milk ducts or something. I hate non-underwired bras but suffer and wear them through pg and bf even though they make my boobs look ridiculous!
Anita make them, although not sure what size they go up to. Try www.figleaves.com/uk/product.asp?product_id=ANT-5041 I started wearing normal underwired bras when my DS was about 10 months and feeding less frequently, just lifted up the cup from the bottom. I would wait until bf is well and truly established before trying this though.