Thankyou for your response!! Unfortunately I only started swift a few weeks ago and so am still unsure with many of the terms. Would you please be able to expand on your response above so it is slightly easier for me to follow along with.

Thankyou so much for this! I wasn't quite sure what had happened but removing the line you recommended seemed to help and now the code runs! A lot of the formatting has changed - certain things overlapping or cut off, but I can always figure that part out again!

Im sorry, what I am trying to do is when they click the button, the mark scheme should appear. So the mark scheme should not be the button, but instead text that appears under the button once it is clicked. Let me update the code to show everything in the view

I am so sorry for bad description, however you guessed spot on anyways! Just implemented this technique and its worked, thank you so so much!!!