Scheduled mails don't seem to be queuing properly

I've posted this issue in the CiviMail forum as http://forum.civicrm.org/index.php/topic,29624.msg126883.html#msg126883. While it's been read 53 times we've not had a reply yet, and after consultation with Oliver Gibson we've thought the best idea is to post it here as an issue. I hope that's ok.

The issue could be that Scheduled Mails are not being queued properly.

We have a Drupal 7.22 installation with Civicrm 4.3.5. We think the issue was also present before a recent update from 4.3.2.

Our scheduled reminders are working, as is our test out going email and all other email tasks such as receipts, confirmations etc.

However, Scheduled emails are not sending.

The process of setting up a Schedule mailing appears to be working fine, and test emails sent during the process work perfectly. The setup screens show the expected number of recipients.

However, when we approve an email for scheduled send two things aren't right:
1. We don't get the email
2. In the table of Scheduled and Sent mailings the columns for Scheduled, Started and Complete are completely blank. The status field says 'scheduled' and all other things appear ok.

This unhelpful behaviour results whether the schedule is for 'send immediately' or some later time. Execute Now also produces no results, although the log reports the operation was successful.

The cron job is set for 10 minutes in our Cpanel, and the Send Scheduled Mailings job in System Settings>Scheduled Jobs is set to run 'whenever the cron job is run'.

We only have one cron job on our site (its for civicrm) and we know it is working because Scheduled Reminders are working. It's format is: wget '[path to our site]/drupal/sites/all/modules/civicrm/bin/cron.php?name=[user]&pass=[password]&key=[our key]'. Time is Minute: '0,10'.

Hope this gives enough data to explore this further. Thanks for your help.