Update works but no logs - Desktop Widget reports 'never updated'

[Peejay]

Thank you for that suggestion, firenice03, I'd forgotten that tweak was available.
Unfortunately it's not made any difference to the history.log or to the Desktop Widget. I also cleaned out the older kernel files recommended for autoremove and the package cache, to no effect.

It's irritating and a bit worrying rather than an operational problem but I would like to resolve it if possible. So I have two further queries:
1. could it be related to the fact that the update process now becomes invisible apart from the disk activity light once it's downloaded the package updates and until it produces the llupdates.log for inspection - or is this an intended change in behaviour?
2. would it be worth deleting the history.log or is this likely to cause further problems?

Thanks very much for the help already given and I'm hoping for further inspiration!

Kind regards