Okay, I managed to load what looks like the main bit of brushwork in Hammer 3.5.
I removed folder paths from the texture names (not sure if that was necessary) and copied the main bit of brushwork into an empty .map file I made in hammer 3.5.
Gotta head out now, but you can probably figure out how to do it...
[Blocked Image: http://img74.imageshack.us/img74/8862/umfw2.th.jpg]