Daughter has since departed for foreign shores accompanied by Discman. No matter what I tried, I couldn't make it play mp3's so come to the conclusion that two reviews for whatever reason were completely in error. Having spoken to her after the first leg of her trip, a 15 hour bus trip during which she said it was going more or less constantly, it seems the glowing reports of battery life in said Sony are on the mark.
Thank you to the respondents.