Have taken the following steps;
Removed Speccy 1.14.288 and reinstalled same - no change
Both opticals are IDE so I changed the ribbon cable (80 connector type) - no change
Changed IDE from Primary to Secondary connector on MOBO, and checked BIOS settings - no change
Researched for any XP System event alerts - there are none
Removed Speccy 1.14.288 and installed 1.13.276 - no change
Ran WinUtilities app version 10.4 and can see both drives fine
CDR0 - AOpen 12x DVD-ROM
CDR1 - AOpen Com5232/AAH Pro (combo DVD-ROM/CD writer)