I have created a report with a few concatenated fields, I want to be
able to hide some defaults I have created in the concatenated field
itself.

For example one of the fields has some car details:
=[CarModel] & " " & [CarColour]

I want to able to hide the CarModel and/or the CarColour if they meet
certain criteria, so for example the CarModel bit would not show if it
was a Ford. So no Ford's would show but the colour would unless it was
a Red then that would be hidden also.

Any ideas would be much appreciated for me to work around this problem.