Well, that plant is getting on towards a pretty complex cross of the ozzie species. D kingianum is in that cross a few times, with the addition of D speciosum, D fleckerii, D jonesii. Anyways, I find all those bar the fleckerii need a fair amount of light, short of leaf burn. The growths start late spring and should grow pretty quickly and you may then get a second set of growth.
The thing is, for the plant to flower, the new p/b needs to harden off. This is where the light levels come into play. Flowering should occur in spring. As far as temps go, again, all the above species are pretty forgiving. I've had mine close to zero during winter. As long as they are kept on the dry side they should be ok.
Is that size 2 1/2 inch??? That is like tiny. That sounds like it is greatly influenced by the kingi.. but with the addition of the speciosum and jonesii, I would have thought it would be taller. Aaah well, more space for more plants. Oh and the old p/bs will keep flowering year after year, generally until the leaves fall off.
and apologies for rabitting on and on, but I do love our natives