Matt, you're not in a Barratt house by any chance? Nearly everyone on my estate in Huntingdon had the same problem, we all had to have our draining boards changed. My neighbour though just wedged his enitire unit up on one side, did the trick but looked silly.
Bad installation. As Dilly suggests try to wedge the draining board up a bit at the furthest end from the sink. May only need raising half inch or so, don't go overboard.
Only other option is to drop the sink. I wouldn't go for that.
Our drainer had water sit in it, I wedged a piece of wood under the lowest bit and warmed the top of the drainer with a hairdrier until it was hot, let it cool and took out the wood. This sort of helped but it's still not great.