I found some of these beetles in the bathroom area, mainly around the window. I couldn't see any larvae in the area.
I have taken some pics, sorry they are not very good. Each beetle is about 4mm long and is dark brown all over. It looks like there are longditudinal markings down the wing cases (which look like tiny ridges).
I was originally thinking some sort of carpet beetle but other people in the house say they are being bitten and I haven't really heard of carpet beetles doing that.