Content duplicating itself

I needed to replace a Contact Form 7 form and set it up in a test directory and re-designed it. Worked perfectly. I went back to the original site and replaced the custom CSS that styled it, changing the form id to the original form id in the code. Also of course replaced the new Form items and also in the Mail section.
Unfortunately it rendered two copies of the form one under the other though only one form tag was on the page.
As the site had only just gone live I didn’t want to take it down again so removed the form from the page and added some text: “coming soon.”
That also duplicated itself on the page online though only entered once in admin.
So now everything I enter in admin is duplicated on the online site.

Does anyone know of what could be causing this? No amount of clearing the cache helps. I may just have to delete the form page entirely and start again if there is no quick fix.

Thanks!