Red colour centres in AlN are bright room-temperature quantum light sources emitting anti-bunched light under optical excitation. We study the temporal, spectral and polarisation behaviour of emitters in commercially supplied AlN on sapphire. The high refractive index limits the photon collection efficiency for a lens above the sample, through refraction and total internal reflection. Applying a macroscopic solid immersion lens which is almost index matched to the semiconductor we achieve a 4.2-fold increase in collection efficiency, yielding nearly one megacount per second detected photon rate.