The message .com
from "Osprey" contains these words:

I drilled a couple of similar large holes, same method as you , but I
kept the drill bit in place until core bit was at least 30mm into
brick.
If you have tct then hammer on ... diamond then hammer off.
Slow, with even pressure.

I found that water helps. The slurry seems to act as further abrasive.

--
Skipweasel
Pay no attention to that man behind the curtain.