Thanks for all your comments.
Some very nice images Pauline, particularly like the Crested Tit, gives me some encouragement.
Thanks for the tip Mick, not tried a User Defined picture style before, will give it a go tomorrow and let you know how I get on.
The more I research the subject the more I am beginning to think its just me expecting too much, certainly looks like the prime lense has the edge on sharpness. Will also give flash ago, got one of those flash extenders a while ago but still to take it out of the package.
Here is a couple of my better Owl pictures taken with the 100-400mm, would welcome some honest views on them.
Gerry