The next installment....
I booted the machine just recently and I am not sure what I did but I
noticed that both the wired and wifi interfaes were up. I took the wired
down
ifconfig enp2s1 down
and it continued to ping my gateway and the bbc. More than that it
allowed be to use aptitude to get firefox.
I tried a number of changes to /etc/network/interfaces and I seem to have
it working. So now back to installing compilers and development tools
As ever I apologise for what were probably trivia questions. My only
excuse is age -- I predate networks and operating systems.