Webform block: reload page with anchor link I have a webform shown in a block that appears at the bottom of my page. 

If I select 'no redirect (reload current page)' when the form is submitted you are taken back to the top of the page and the confirmation message is shown above the form, so unless you scroll down it appears as if nothing happened.

If I select 'Custom redirect URL' and enter [current-page:url]#my-form when the form is submitted you do get taken down the page to the form only now the confirmation message is shown at the top of the page, so unless you scroll up you won't see it.

Is there a way to refresh the page, scroll down to my form and show the confirmation above it or do I have to use AJAX for this?
You can achieve that by using the Webform Ajax module

This module adds AJAX support to Webform (3.0 and above).
As a first step it focusses to simply add form AJAX paging and submit. Form submissions get ajaxified including prev/next pages. Especially for multipage forms, this leads to faster loading (less data transfer), better usability and finally smaller server load.