Just deleted all the old 5.1 files on my test site. I found that in place the update button would not work, so I decided to nuke and pave.
Uploaded all 5.4 files with ftp, then went and found a copy of the missing config file and uploaded that and I have a 5.2 site.
However I have no pages. The standard about/work/blog/contact pages are not there.
If I add a new one and enable it in settings/navigation, its not there either although the new page called Test does show up onthe Navbar.
Any ideas what is happening here? Its all a bit broken.