@nigel Thanks for the report and initial investigation. That’s a funny one.
Take a look at the following forum thread where @Tony_Cristiano also had what may have been a similar or related issue with postgresql not being available:
There @Flox went for the force re-install approach and after @Tony_Cristiano then re-established the enable default and started the service it seems to have sorted itself.
Your issue may not be related but take a look to see as we have yet to get to the bottom on what happened in @Tony_Cristiano reported incident.
Thanks.