Thanks, the updated client found the coins 

I didn't know about this new version (mine was v0.9.0, released a couple of weeks ago when the halving hard fork happened), and I've been checking for a new version at maxcoin.co.uk but it's been offline at least since yesterday.

If anyone else needs the updated client it can be found here: https://github.com/Max-Coin/maxcoin/releases/tag/v0.9.1.0