Clearnav vario GPS

Three or so years ago, despite having been a Cambridge rep for many yeas, I bought a Clearnav vario , recommended by Dave Ellis. There are several screens
of programable options; I found accessing these
in flight using two knobs, even the audio volume, an impossible task; I confess that I am of the persuasion that one switch/knob per function is the right approach.

Among the few things I wanted to change is the averaged (smoothed) ROC
time constant is the 20sec value, much too short for my taste.
Beats me why this is not user controlled.
But I digress!
Unable to find an email for Paul REmde, I ask here what is the use
of the supplied GPS antenna when there seems to be no data storage?
There is a Lat/long display, really useful when scratching at 1000 ft! (not)
What am I missing?

John Firth