I can tell that I will be giving away the links to Pete's posts to a lot of people. Thanks for that.

Some of the wireless firmware is in contrib, so that might need to be added to the sources along with non-free.

Bug fixed

Hopefully its useful.

Some of the wireless firmware is in contrib, so that might need to be added to the sources along with non-free.

I do tend to be a bit um primary school about things

I wouldn't have done all that if I thought _you_ were an idiot.

Hopefully its useful for a genuine novice at some point.

In my defence I used to step lots (over 100) of 'Doze refugees through the basics.
Face to face though  where  its easier to assess skills etc.

In your case just add non-free and move on

aside:

/aside

Meantime here is a walk through of one method of finding and installing software.

1./ lspci (list hardware on your PCI buses.)
     you visually grepped out the atheros bit...

2./ use YOUR system tools first
     apt-cache  is a good place to start or synaptic => search
     apt-cache search  foo
     apt-cache show fooz
There is also :
     dpkg -S packagefooz
     dpkg -L packagefooz
There are man pages or even plain old --help -h

synaptic actually uses these in the background ... well OK sometimes they are built in versions ...

3./ look to your local  devuan
    /usr/share/doc/fooz/ or fooz-doc
    apropos fooz
    man fooz  and or info fooz
   
4./ look upstream debian and then :
     There are links that may be helpful
     In this case as its firmware less useful
     But you may find information that helps with the last step.

5./ your favourite search engine
(rinse repeat)
Follow barely understood instructions down cut and pasted roads to confusion.
Drink too much cool aid and eventually realise NO ONE really understands all of this.
Not even Linus

Always backup any config files and you will hardly ever break stuff.
I break stuff all of the time.
Its how I  learn things best :  by making mistakes and f i x i n g them

minimalish example

1 [Wed Jun 28 05:45 PM] pete@mingus:~$ lspci

2 [Wed Jun 28 05:45 PM] pete@mingus:~$ apt-cache search atheros
firmware-atheros - Binary firmware for Atheros wireless cards

3 [Wed Jun 28 05:46 PM] pete@mingus:~$ apt-cache show firmware-atheros
Package: firmware-atheros
Source: firmware-nonfree
Version: 20161130-3
Installed-Size: 8047
Maintainer: Debian Kernel Team <debian-kernel@lists.debian.org>
Architecture: all
Suggests: initramfs-tools
Description: Binary firmware for Atheros wireless cards
Description-md5: cc64d612094e73015861cf2915345869
Multi-Arch: foreign
Homepage: https://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git
Section: non-free/kernel
Priority: optional
Filename: pool/DEBIAN/non-free/f/firmware-nonfree/firmware-atheros_20161130-3_all.deb
Size: 3131536
MD5sum: 1b4ff70d8293e5e1b2d3480ee9cc6a3b
SHA256: 98ecdada8228a647007a816a30daec33436bb58e53057b5e8f8ad45b9a85b881

There is a second version available to my system that I have snipped.
However this blob of terse info tells you much that is useful and wise.

Including:
     where the source is maintained (kernel.org )
     That it is non-free software (multiple times)
    There are also mentions of "initramfs-tools" "firmware-nonfree"
     and "linux-firmware" 
So Its worth also have an apt-cache search for those just for some context.

Probably all you need to do is:
NOTE I do NOT need this this package and it will be removed
((my atheros is a nice girl and never reads nasty dark code 
She was also cheap.))

The following is edited for sanities sake

4 pete@mingus:~$ sudo apt-get install firmware-atheros
<snips>
The following NEW packages will be installed:
  firmware-atheros
0 upgraded, 1 newly installed, 0 to remove and LOTS not upgraded.
Need to get 3131 kB of archives.
After this operation, 8191 kB of additional disk space will be used.
Get:1 http://au.mirror.devuan.org/merged jessie-backports/non-free i386 firmware-atheros all 20161130-3~bpo8+1 [3131 kB]
Fetched 3131 kB in 12s (260 kB/s)
Selecting previously unselected package firmware-atheros.
(Reading database ... 149922 files and directories currently installed.)
Preparing to unpack .../firmware-atheros_20161130-3~bpo8+1_all.deb ...
Unpacking firmware-atheros (20161130-3~bpo8+1) ...
Setting up firmware-atheros (20161130-3~bpo8+1) ...
 
5  pete@mingus:~$ apropos atheros
atheros: nothing appropriate.

6 pete@mingus:~$ apropos firmware
firmware: nothing appropriate.

7 barry@white:~$ ls /usr/share/doc/fir[TAB][TAB]
firefox-esr/            firmware-intel-sound/   firmware-linux-nonfree/
firmware-amd-graphics/  firmware-linux/         firmware-misc-nonfree/
firmware-atheros/       firmware-linux-free/

7 pete@mingus:~$ ls /usr/share/doc/firmware-atheros/
changelog.Debian.gz  copyright

8 pete@mingus:~$ zless /usr/share/doc/firmware-atheros/changelog.Debian.gz

Which has nothing useful for me at this time.
Proving once again that non-free stuff totally sucks.
However sometimes you have to use it.
The installer may even taken the time to add this module to your initramfs
But if you can boot without it (and unless you booting over your wireless network ....)

try :  ip l     and or   ip a
or finally wih sudo or su :

[2] [root@mingus]: /home/pete$ iwconfig
wlan0     IEEE 802.11  Mode:Master  Tx-Power=20 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off

eth1      no wireless extensions.

lo        no wireless extensions.

br0       no wireless extensions.

eth2      no wireless extensions.

dummy0    no wireless extensions.

eth0      no wireless extensions.

Foolish optimist that I am, I would have expected the installation process to have determined that it needed that package. I have this unrealistic expectation that the

apt install task-desktop

would have pulled in the relevant packages if they were absent, as it includes Wicd, and there is a Wi-Fi chipset visible on lspci.

Unfortunately, I have several major family events (some good, some bad) to deal with, so I don't have time to play right now.

Thank-you for the helpful follow-up - I do appreciate it, even if I can't act on it immediately.

lspci shows Wi-Fi device is Qualcom Atheros Device 0041 (rev 20)

After a bit of searching, I think the device is an ath10K device, for which there is support via backports

https://wireless.wiki.kernel.org/en/use … /backports
and
http://drvbp1.linux-foundation.org/~mcg … backports/

before I crank my way through the above process, is there an automagic way of achieving the same using apt-get or Synaptic, as the backports process says Wi-Fi will stop working and need special handling each time there is a kernel upgrade.?

uname shows current kernel is 3.16.0-4-amd64 SMP #1 Debian 3.16.43-2+deb8u1 (2017-06-18) x86_64

Thanks