Hey Jonathon, well firstly, the guitar was actually a custom made for me. It is still, luckily, under warranty so if anything is seriously wrong I should be covered. Hence why my tech was suggesting that a new neck could be one option - we were talking about fret-dressing and other such solutions, and it ended up getting into the price range of a whole new neck anyway.
But if he can't sort it out easily, I'll take the neck off and post it back to the maker and get him to sort it.
Mark, that sounds like it. What do you mean by getting it properly humidified? Is this a process someone carries out on the wood, or do you mean I should keep a humidifier where I store my guitar? As you say, though, the problem is one that may well naturally rectify itself; my tech was saying that when the weather goes back to how it was when the guitar was made, then the neck should hopefully fix itself. Obviously though, this is not much of a solution if the neck is only perfect 6 months a year!