Thanks for this @russian-dima . You are correct that my logic was wayward. I did focus in on the onReady data but must admit that my limited knowledge lead me to think that the order was irrelevant when clearly it isn’t - another lesson learnt!
I have also added to what you have offered above to enable wixStorage to operate correctly on page 2 to ensure that the dropdown changes as per the user selection.
I do have one further question relating to this (although it may be a case that I need to start a new thread for it). On page 1 of my setup I now have a repeater with container boxes which each bear relation to the #classDropDown. Is it possible, either via onClick on the container or by adding a button to the container, to be redirected to page 2 and for the #numberDropDown to then build and show the values which relate to the class on the container which was clicked.
So an example would be that on Page 1 I have a repeater with 2 items. One is Class 1 and one is Class 2. When the container on class 1 is clicked, I would be redirected to Page 2 and the #numberDropDown on there would list 1-10 and if I click on the Class 2 container on page 1 the dropdown on page 2 would list 11-20. I suspect it can be done, as it feels quite similar to a dependent dropdown (just using a button to replace the first dropdown) but I would prefer to know it is possible before spending too much time on it 
Thanks very much for all of your help