[Snapshot Pro] Snapshot not deleting temporary backups local storage

Hi Team,
Snapshot isn't removing old backups stored locally on the hosting web server and the folder has crept up to around 700MB.

Is this an issue you have come across before?

The Wordpress install is a multisite, and I thought I had it backing up to the WPMUDEV servers only.

Please let me know if I can provide any more information.

Cheers

Jack