Jeff Layman submitted this idea :
Could you tell me how well it works with "hidden" mould growth? By that I
mean the mould that grows on walls behind cupboards, wardrobes, etc, on the
backs of those wardrobes, and even inside the wardrobes, drawers, and
anything enclosed.

Your moisture must be from somewhere and its source/cause needs to be
found. I have lots of cupboards, drawers and wardrobe space - none of
which suffer such problems. I have an especially large built in
wardrobe, occupying a full wall (maybe 16' wide) which I built 30 years
ago and is packed with clothes, never any problems there. It is
back-less, just a papered, plastered, cavity party wall behind it and
all 6x doors are usually kept closed.