Replying to my own post - hope it might help someone else one day!
Finally tracked down the problem
- HP2100 was installed as the default "HP Laserjet 2100 Foomatic/pxlmono (recommended) (HP/LaserJet_2100-pxlmono.ppd.gz)"
Changing to use LaserJet 4 emulation instead (select the ppd in the SuSE YaST printer config pull-down menus):
"HP Laserjet 2100 Foomatic/ljet4 (HP/LaserJet_2100-ljet4.ppd.gz)" makes it work properly.
I would acknowledge where I saw this suggestion but I can't find it again - been looking pretty manically...