Created a new 2013 Online Trial.
Navigated to Solutions under Settings and Imported a 2011 Solution without issues (very few customisations and only 2 custom entities)
However the next day I accessed the instance and when I navigate to the Settings area neither the 'Solutions' or 'Customisations' are visible as tiles.
I can open a form e.g. Account and customise the form but when I go into the Settings area they Solutions tile doesn't exist.
No issues with Service Health on Office 365 Admin and I'm global administrator so not a permissions issue.
Also notice that the two custom entities which are set to display in the sales area are not displaying in the navigation path and I can only access from a linked entity (Account).