Thanks for the quick response.
The quote marks above were inserted just in this post, but not the coding. I was intending to use backticks as suggested in the WP post markup.
I have tried your test by coding .slick-form {display: none;} into the styles.css for the theme. (is that the right place?) I assume it can be inserted anywhere in the styles.css?
The form still appears briefly in the widget box and then moves just as before. No change
