Stu -
Create another submit page with H1 Submitions Closed Temporarily. (that's it)
Rename your current submit page to Ready_to_open.html
Upload the NEW submit.html
When you're ready for submits, rename submit.html to submit_to_close.html
Then rename Ready_to_open.html to submit.html
Then if you ever need to close submits for any reason, it takes about 10 seconds to reverse this process.
Sorry if my Dutch is rusty
