The backup is complete just the post processing is failing. These are run from a cron.
From the logs:
[150714 02:33:55] Continuing post processing file <root>/administrator/components/com_akeeba/backup/site-macrotoneconsulting.co.uk-20150714-012503.jpa
[150714 02:33:55] Akeeba\Engine\Postproc\Onedrive::Akeeba\Engine\Postproc\Onedrive::initialiseConnector - Validating the OneDrive tokens
[150714 02:33:56] Akeeba\Engine\Postproc\Onedrive::Akeeba\Engine\Postproc\Onedrive::processPart - Simple upload. Proactively deleting files with remote path website/backups/site-macrotoneconsulting.co.uk-20150714-012503.jpa
[150714 02:33:56] Akeeba\Engine\Postproc\Onedrive::Akeeba\Engine\Postproc\Onedrive::processPart - Performing simple upload
[150714 02:33:57] Akeeba\Engine\Postproc\Onedrive::Akeeba\Engine\Postproc\Onedrive::processPart - Simple upload failed, 500: Error invalidRequest: @name.conflictBehavior should be provided inside the 'item' parameter
[150714 02:33:57] Akeeba\Engine\Postproc\Onedrive::Akeeba\Engine\Postproc\Onedrive::processPart - Maximum number of retries exceeded. The upload has failed.
[150714 02:33:57] Failed to process file <root>/administrator/components/com_akeeba/backup/site-macrotoneconsulting.co.uk-20150714-012503.jpa
[150714 02:33:57] Error received from the post-processing engine:
[150714 02:33:57] Error invalidRequest: @name.conflictBehavior should be provided inside the 'item' parameter \n Error invalidRequest: @name.conflictBehavior should be provided inside the 'item' parameter \n Error invalidRequest: @name.conflictBehavior should be provided inside the 'item' parameter
Manually trying to transfer the backup file later (obviously) immediately failed with a '-1' retuirn.
I thought originally that it might be a small OneDrive hitch (which it may still be) but suspect from the message above something else might have changed?