Hello David
The problem seems to be on WebAsyst's server rather than my site.
The only page I upload to my server is my modified
index page where I, in this case, added one product and one
Add To Cart button. Everything else, I think, is on WebAsyst's server and is updated when I change things in my Store.
When I go into my Store on WebAsyst and add products and revise category descriptions, these changes don't appear on the .php page that is linked from my site to WebAsyst, although these changes do appear on the
Shop page on WebAsyst when I access it through my Store.
On another forum somebody asked me whether I was using Shop-Script Free or WebAsyst. I thought they were one and the same but maybe I'm missing something important here - remember I'm only semi-computer literate!

.
Thanks, again, for your prompt reply and all your help.
Regards
Bill