I need a hole (for a cable) from a cupboard, through a ceiling and into my loft. I know exactly where I need the hole to be in the cupboard ceiling, but I can't get a drill into that space. So, the hole needs to be made from the loft space.
However, between where the hole needs to emerge in the cupboard, and where it needs to start, are two walls and a hatch. Hence, I can't easily work out where to start drilling.
I figure I need a way to "survey the land" so that I can determine where to start drilling - basically a series of right angled lines that lead from the cupboard to the hatch, up through the hatch and back to where the hole needs to start.
But, I've no idea on how to do such a task with any accuracy.