Richard,
You are experiencing a bug I just discovered Monday. There will be a new version coming out soon. If you are comfortable changing the code open up fordson/layout/course.php and find this variable:
$hasfpblockregion
delete it and change it to this:
$hasfpblockregion = ($PAGE->theme->settings->blockdisplay == 1) !== false;
Then clear Moodle cache. You should see a Course Block button and when clicked your blocks will slide down.
New version will be released maybe later today though.