OK, FPC 3.0.0 seems to work with Lazarus 1.8.
After building I set the widgetset to qt5 in build options. This gave a compile error at the last line 'end.' saying Lazarus could not be built.
Changing qt5 to qt solved the problem, so I take it qt5 support isn't 100% yet.
BTW installing the package anchordockingdsgn ran flawlessly with version 1.8.