If you don't have glideslope capture, or it is u/s or not available, you should only descend in accordance with the "localiser only" profile. What would be the reason to go any lower? This will usually require another distance fix such as DME, locater beacon or marker beacon. In some parts of the world ATC will issue clearances to lower altitudes and assume that the pilot will comply with any other published restrictions. Classic case is Indonesia where the MSA's are very high, but they will sometimes clear you on nonprecision approaches down to the FAF or even minima while you are miles away and still subject to terrain limitations. In Oz we sometimes get a clearance to "...ft RADAR LOWEST SAFE"
but anyone not hearing these words would be most unwise to go below the charted limits.