Can you advise on online backups, backup management tools or services?
This depends on how you would want to access the space. If you prefer to be "hands on" in backing up, one solution would be a shared hosting package, see http://webarchitects.coop/shared-hosting, with an SSL certificate for secure access to the data, and perhaps an OwnCloud installation.
If you are thinking more of automated backup and restore tools then you could have some space on one of our backup servers and use Backupninja: https://labs.riseup.net/code/projects/backupninja. Backup space pricing is here: https://webarch.net/backups
We could help set up all this, please contact us by email to discuss: firstname.lastname@example.org