It OK Arthur, re your point on the histogram - point taken I agree, what I was trying to say with the flash - for my purpose it is primarily to fill in some shadow i.e. where relatively speaking the light level is low, so a little additional light is significant. As this little light is also added to a brightly lit area it is not really having a great effect there because it is a little additional light to what is already a bright area In other words the effect is greater on the dark areas and pretty well almost ineffective/insignificant on the lighter areas.
Jon