I've fit (fitted?) a banister to the mother in law's wall.
4 brackets, about 40mm round against wall, three screws in each.

3 went on OK, one is in an area where there is no solid wall.
I glued some plugs in but it's not happening.

At home i'd drill big holes and glue/hammer fat dowels in and screw into
that but I want to contain whatever destruction I cause behind the bracket

I can't decide what to do that would cause least disruption to the decor.

Ideas appreciated.