After my last post, I found that the ‘benq’ setup wasn’t working for headphones, which is my primary use for sound on the lappy. So, I found another post which says that if you suspend and resume the laptop (Fn-F1), sound ‘magically’ starts to work. So I updated /etc/modprobe.d/alsa-base again, this time using the line:

options snd-hda-intel index=0 model=auto

Then I fired up amarok, muted the “Front” mixer control and am now happily listening to tunes via the headphones. I’ll try again after rebooting and update — hoping for a solution which Just Works.