I've now updated to kernel 4.15.1
~ >uname -a Linux george-CM6330 4.15.1-041501-generic #201802031831 SMP Sat Feb 3 18:32:13 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
It makes no difference to the symptoms.
I've now updated to kernel 4.15.1
~ >uname -a 041501- generic #201802031831 SMP Sat Feb 3 18:32:13 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Linux george-CM6330 4.15.1-
It makes no difference to the symptoms.