My problem is that I have a summary field that works as I intend on the parent file by showing the summary of found records only. However when that same field is displayed on a child file it shows all summary of all the parent records. Can anyone explain how I can have the display on the child file correspond with the display on the parent file i.e. just the found records on the parent file.

The short answer is you can't, relationships aren't affected by the found set.

You could however create a new field in the parent file and flag all the records in the found set either as being found with 1 and then add up the found set in the child db or set the value from your summary field value.

Thanks for the suggestion. Sorry but how do I "flag" a field? I have tried creating a new calculation field in the parent file that is equal to the summary but it shows the found records figure when on the parent layout and the all records figure when displayed on a child layout . So I am no further ahead.