I think your template knows too much about what the url should look like, the common way this is written is like

<a href='[% form.fudgy_href %]' target='_blank'>
[% form.FormName %]
</a>
or
<a href='[% url_from_form( form ) %]' target='_blank'>
[% form.FormName %]
</a>
[download]

That way the template doesn't change if the url changes, or if you switch from the  foo?rm=foo style to the  /foo/rm/foo style

Also template modifiers don't get tempted to delete all the logic ... that belongs outside of the template :)