Super, thanks Dr. Sassi I will try that.
One of the issues I found with my method of keyframing the Display tag > Visibility is that when the opacity is 0% it stills casts a dark shadow but if I start it's opacity at 3% there is no shadow initially and as the opacity increases to 100% the shadow and object fades in as normal, so that might be a work-around.
But I will also try your method and see how it works. Thanks for taking the time to answer my query