On Mon, 24 Dec 2018 17:44:35 +0000, ARW wrote:

In the end we drilled from inside to out and we were both 12 inches out
on the vertical. The kitchen floor is reasonably level so what went
wrong?

You counted brick courses up from the floor in the kitchen and up
from from the paving/ground level outside but forget the step up into
the kitchen.

--
Cheers
Dave.