Hey Simon,
A third party code (Google conversion frame) is causing the space. You will either need to remove it or contact the code provider on how to hide it.
For the fields, please add the code below in your Appearance > Customize > Custom > Global CSS
body .gform_wrapper .top_label .gfield, body .gform_wrapper .top_label li.gsection.gf_scroll_text {
margin-bottom: 0em !important;
}
body .gform_wrapper ul li.gfield {
margin-top: 0;
}
Thanks.