I tried to do some more mapping today, but it looks like my Nokia (6120 Classic) is kind of dead. It did the same thing it did the other day — crashed with an "out of memory" error and erased my work — so I figure I'm either going to have to work out what's causing the problem or fork out millions to upgrade my handset.
I started taking street names in the little pocket of un-mapped Algester. I noticed a few of my waypoints took, so I'll work out what I've still got, and go back another time. I'm still massively annoyed at Symbian, Nokia, and the universe in general.