Hi Simon, this is a bit strange, 15.10 should build against qt5 and vtk6. I will double-check, the packages are quite fresh (just like 15.10 itself) and may have some issues. Please also note that 15.10 has some outdated packages which will fail with woo (in particular, the packaged ipython does not support qt5 yet -- you will have to install those through pip, but it should eventually work).
Your best bet is to compile from sources, using qt4 (or qt5 and ipython from pip) and vtk6 as explained here, something like scons features=qt4,vtk,opengl,openmp,gts CPPPATH=/usr/include/vtk-6.2:/usr/include/eigen3 (the CPPPATH is needed to select the right VTK lib).
I check the package and let you know. If you go the source-compilation way, please also keep me updated here.