Thanks. Ran the update via GUI but no error messages. Here is the log:
The following packages were automatically installed and are no longer required:
kid3-core libcgmanager0 libflac++6v5 libgexiv2-2 libglade2.0-cil
libid3-3.8.3v5 libjs-sphinxdoc libjs-underscore libllvm7
libmono-accessibility4.0-cil libmono-data-tds4.0-cil libmono-ldap4.0-cil
libmono-sqlite4.0-cil libmono-system-componentmodel-dataannotations4.0-cil
libmono-system-data4.0-cil libmono-system-design4.0-cil
libmono-system-enterpriseservices4.0-cil libmono-system-ldap4.0-cil
libmono-system-numerics4.0-cil
libmono-system-runtime-serialization-formatters-soap4.0-cil
libmono-system-transactions4.0-cil
libmono-system-web-applicationservices4.0-cil
libmono-system-web-services4.0-cil libmono-system-web4.0-cil
libmono-system-windows-forms4.0-cil linux-headers-4.15.0-47
linux-headers-4.15.0-47-generic linux-headers-4.15.0-48
linux-headers-4.15.0-48-generic linux-headers-4.15.0-50
linux-headers-4.15.0-50-generic linux-headers-4.15.0-51
linux-headers-4.15.0-51-generic linux-headers-4.15.0-52
linux-headers-4.15.0-52-generic linux-headers-4.15.0-54
linux-headers-4.15.0-54-generic linux-headers-4.15.0-55
linux-headers-4.15.0-55-generic linux-headers-4.15.0-58
linux-headers-4.15.0-58-generic linux-headers-4.15.0-60
linux-headers-4.15.0-60-generic linux-headers-4.15.0-62
linux-headers-4.15.0-62-generic linux-image-4.15.0-47-generic
linux-image-4.15.0-48-generic linux-image-4.15.0-50-generic
linux-image-4.15.0-51-generic linux-image-4.15.0-52-generic
linux-image-4.15.0-54-generic linux-image-4.15.0-55-generic
linux-image-4.15.0-58-generic linux-image-4.15.0-60-generic
linux-image-4.15.0-62-generic linux-modules-4.15.0-47-generic
linux-modules-4.15.0-48-generic linux-modules-4.15.0-50-generic
linux-modules-4.15.0-51-generic linux-modules-4.15.0-52-generic
linux-modules-4.15.0-54-generic linux-modules-4.15.0-55-generic
linux-modules-4.15.0-58-generic linux-modules-4.15.0-60-generic
linux-modules-4.15.0-62-generic linux-modules-extra-4.15.0-47-generic
linux-modules-extra-4.15.0-48-generic linux-modules-extra-4.15.0-50-generic
linux-modules-extra-4.15.0-51-generic linux-modules-extra-4.15.0-52-generic
linux-modules-extra-4.15.0-54-generic linux-modules-extra-4.15.0-55-generic
linux-modules-extra-4.15.0-58-generic linux-modules-extra-4.15.0-60-generic
linux-modules-extra-4.15.0-62-generic python-acoustid python-audioread
python-configobj python-levenshtein python-mysqldb python-pymad
python-pyparsing
Use 'apt autoremove' to remove them.
The following packages will be upgraded:
libtiff5 libtiff5:i386
2 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 317 kB of archives.
After this operation, 0 B of additional disk space will be used.
Get:1
http://archive.ubuntu.com/ubuntu bionic-security/main i386 libtiff5 i386 4.0.9-5ubuntu0.3 [164 kB]
Get:2
http://archive.ubuntu.com/ubuntu bionic-security/main amd64 libtiff5 amd64 4.0.9-5ubuntu0.3 [153 kB]
Fetched 317 kB in 2s (190 kB/s)
(Reading database ...
[snip]
(Reading database ... 686728 files and directories currently installed.)
Preparing to unpack .../libtiff5_4.0.9-5ubuntu0.3_amd64.deb ...
De-configuring libtiff5:i386 (4.0.9-5ubuntu0.2) ...
Unpacking libtiff5:amd64 (4.0.9-5ubuntu0.3) over (4.0.9-5ubuntu0.2) ...
Preparing to unpack .../libtiff5_4.0.9-5ubuntu0.3_i386.deb ...
Unpacking libtiff5:i386 (4.0.9-5ubuntu0.3) over (4.0.9-5ubuntu0.2) ...
Setting up libtiff5:amd64 (4.0.9-5ubuntu0.3) ...
Setting up libtiff5:i386 (4.0.9-5ubuntu0.3) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
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Seeing so much stuff listed as no longer required, I used apt remove as the log suggested, and suddenly the widget tells me my system was recently updated! Was that why, do you think? Anyway, thanks!
Will test the system for a bit before marking "SOLVED" but at the moment, it looks okay.