The reason why I needed another was that my old laserdisc player which has a fairly good specification (2-sides, PAL/NTSC, analogue/digital sound) has decided to be VERY awkward about loading disks - it'll only do it if I put the disk in the drawer, switch off, let it power down, then switch on, let it go through its startup routine, then press play. Even then it's got very picky about which disks it'll play. My guess is that it's out of alignment and/or needs a thorough clean. I can open the casing and vacuum, but beyond that I'm at a bit of a loss, and Pioneer pointed me at a service company that quotes £60+VAT for a no-warranty repair, which means it really isn't going to happen any time soon.
The "new" machine will tide me over while I try to find a cheaper solution for the other one. Somewhere there has to be a "Laserdisc player repair for dummies" site, I just need to find it. And if all else fails I can sell the old one in "as is" condition and probably get more for it than I paid for the replacement.