Graham Devian Yes I think i missed a {% endif %}
from the very bottom of the file (corrected in my file you linked)
thanks for spotting it
I just run a test upload of all the files and everything works now

as for Bootstrap 4 I have not looked into it yet but feel free
no permission or credit is required for any code I create
I advise you to avoid too many of the 'dom' effects as a lot of mobile browsers cannot run them simple is better and more compatible with mobile browsers