I feel like an idiot! I sent my application off around the 12th July, and thought it was weird that I hadn't heard anything back by now (6th August) so logged on to my NATS account and reviewed my profile. I fixed a grammatical error that I came across then finished the thing off - but I think I've sent off my application again because I received another email from NATS, the same as before, saying that they had received my application! I'm aware that you can only apply to NATS three times, hopefully I haven't stupidly used up two of my three chances!