  Large (> 100 mm$^3$), relatively pure (type II) and low birefringence single
crystal diamond can be produced by high pressure high temperature (HPHT)
synthesis. In this study we examine a HPHT sample of good crystalline
perfection, containing less than 1 ppb (part per billion carbon atoms) of boron
impurity atoms in the {001} growth sector and only tens of ppb of nitrogen
impurity atoms. It is shown that the boundaries between {111} and {113} growth
sectors are decorated by negatively charged nitrogen vacancy centres (NV$^-$):
no decoration is observed at any other type of growth sector interface. This
decoration can be used to calculated the relative {111} and {113} growth rates.
The bulk (001) sector contains concentrations of luminescent point defects
(excited with 488 and 532 nm wavelengths) below 10$^{11}$ cm$^{-3}$ (10$^{-3}$
ppb). We observe the negatively charged silicon-vacancy (SiV$^-$) defect in the
bulk {111} sectors along with a zero phonon line emission associated with a
nickel defect at 884 nm (1.40 eV). No preferential orientation is seen for
either NV$^-$ or SiV$^-$ defects, but the nickel related defect is oriented
with its trigonal axis along the <111> sector growth direction. Since the
NV$^-$ defect is expected to readily re-orientate at HPHT diamond growth
temperatures, no preferential orientation is expected for this defect but the
lack of preferential orientation of SiV$^-$ in {111} sectors is not explained.
