Checksums not working with /profile/edit/

On Demo I've:

• created a user
• set the CiviCRM Edit Profile permission to allow Anon (not on Civi Demo, but on production and local vanilla)
• created a mailing with a checksum link <- method obtained from docs
• tried to use the link generated in a borwser

• End up with Access Denied page.

to save any going off hunting it, the URL I'm using is:

http://d46.demo.civicrm.org/civicrm/profile/edit?reset=1&gid=1&

Unknown macro: {contact.checksum}

&id=

Unknown macro: {contact.contact_id}

I've also used:

http://d46.demo.civicrm.org/civicrm/profile/edit?reset=1&gid=1&id=

Unknown macro: {contact.contact_id}

&

Unknown macro: {contact.checksum}

I've tried this on different sites. On demo I cannot access the drupal permissions to ensure that CiviCRM edit profiles is activated. but have tried on a vanilla install, and a production site. I get the same result from all of them.

is this a bug or am I missing something obvious?