According to your last log there is an issue with ACPI and the network device (error after a 3 minute silence), I thought it might help switching it off.
It obviously did’nt, bugger 
I must admit that I have not taken any specific attention to running the x86 version on a macbook in the sense of checking which kernel config parameters need to be set/ unset.
Anyone out there, with information re. running linux on a macbook (be it Debian or Ubuntu) please report.
This problem seemed to disappear when I originally upgraded to 2.246, but now it seems that I can’t upgrade past 2.224 as the “check update” does nothing.
Is there some way to force an upgrade to the 2.246 version, so that I can test to see if this network issue remains?
Yes, you could download http://updates.volumio.org/x86/volumio/2.246/volumio-2.246-2017-07-30-x86.img.zip, unpack and flash it directly.
When you say “flash it directly”, do you mean install the update from the command line or do you mean re-install Volumio from scratch.
If the former, where do I find instructions to install the update from the command line.
I’d rather avoid the latter as for some reason Volumio takes many hours to index my NAS music library.
Update: As the zip image is 4GB I assume you meant the latter. If so, to avoid having to re-index my music library from scratch, where do I find Volumio’s library database file so I can make a backup of it. After I reinstall I can just copy it back, if that’s possible.