Update:
Broken Etrex 20 sent off to Garmin & received what looks like a brand new 20x almost by return of post.
The pre-installed maps are fine for me (1), perhaps even a little clearer than Velo Maps which I was using
Routing (which I use occassionally) seems to be a bit different from the results I was getting. Presumably would go back to what I'm use to if I chose to load Velo Maps & the associated preference settings.
I like the fact the installed maps cover Western Europe, that will be useful in August.
Overall I'm happy with the outcome.
(1) mild myopia allows me to get away without using distance glassesfor most things and I get an stay of execution for the onset of presbyopia - Win Win