Try removing the jQuery link you added to the top and move all of the other scripts to the footer area in RSD.

What I think is happening is the slider js' are being called after the tab loads so Eric is correct the css and styles in the head and the scripts in the footer. So this may work?
Also the lengthy load time may be from the duplicated scripts plus the amount of them being loaded up front, plus all the images of course on one page which are I think are also being pre-loaded.

These go in the head

These go in the footer

Foundation has a jQuery library included and RSD adds the font call plus a polyfill

Thank you to each of you who have taken the trouble to advise me and give ideas. I really appreciate it.
I have implemented, in turn, each of the solutions that you proposed yesterday/day before.
None of them actually worked - but this is most likely me, in my inexperience, that I have implemented wrong, and certainly not the advice/code that you have given me!
Website Insight also indicates that the page is too big, too many pictures, too many requests etc. so I feel it is time for me to reconsider my design!
Thanks again.
Nick

Another approach could be to load the html of each slideshow into a common div using ajax or jquery load when each tab was selected. (Sometimes I dont give up on a idea.....6 months from now who knows ? or 9 months etc...)