Should have been more specific ...
mounting not a problem, I've got loads of double sided tape and silicone.
It's the cable routing that I'm trying to figure out.
At a guess id say drill through the brick at a 45° and then push the cable rods through and hope they pop out in the loft, then feed the cable through.
Any advances on that?
I'm going for 2 live sounders on the sheer principle that I've already got them both.
It is bells only, but I'm hoping to build something that alerts keyholders.