I did some research, and found all the sony Discmans (Discmen?) with compatible lasers, and set up an eBay saved search.
To be honest, it's not something I spend much time thinking about recently (me and my girlfriend just split up), and rather than let it sit somewhere I thought I'd hand it over to you guys. (I told Blue already I had it, and was going to work out a good way so that people didn't end up in a bidding war).
Here's the saved search: Discman (d-2, d-3, d4, d-9, "d 10", "d 11", "d 12", "d 15", "d 20", "d 22", "d 33", "d 40", "d 90", "d 99", "d 100", "d 180k", "d 800k", "d 802k", "d t20")
Some of them are 220's some are 160's, and I can't remember which, but it shouldn't really matter too much, right? Anyway, enjoy, don't bid too much (£3 inc shipping is quite achievable).