I listened to the audiobook version.
This is so far the worst Doctor Who book I read / listened to. I keep forgetting about it too, so apparently my brain is trying to erase the memory. In the beginning, the way animals and all sorts of things were turning into gold and then moving was interesting, but when they were crawling around the caves it got quickly boring, and it couldn't recapture my interest. I wondered if it was just because I listened to it and not read it, but looking through the reviews I saw that other people had similar experiences with it.
I didn't like Don Warrington's reading. For some reason his voice annoyed me, and I felt he couldn't capture the Doctor's way of speaking either. He was more successful with the African characters.
The characters I can't remember at all. I remember that there was a guy and a woman that were running about, but nothing of them was committed into memory.
Overall, I don't recommend this book. It can be given a shot, but it wasn't that good. I also recommend staying away from the audio version. The reading makes it even worse.