I am just establishing my backup technique for Heroku and i am after a lot of what i have to safeguard against.

Clearly I have to ensure I look out onto safeguard loss of data through my very own mistakes or malicious attacks etc but will i should also safeguard against Heroku messing up and losing/corrupting my data?

I.E. Can one depend on heroku to possess sufficient redundancy for hardware failure etc or should i safeguard from this.

There's no harm in getting several backup - I personally use a method much like http://trevorturk.com/2010/04/14/automated-heroku-backups/ - to obtain a backup file to outdoors of Heroku (must i ever require it) however i have 100% confidence in Heroku to tell the truth but it is for my very own sanity.

Heroku now offers an add-onto backup your database. It's known as PG Backups.

In the add-on-page:

Heroku's database backup solution. Captures and reinstates backup copies in the shared and/or devoted PostgreSQL databases to have an application. Imports data from a current database backup, and exports backup copies for off-site storage.

You can preserve by hand 2 or 7 backup copies. You may also have daily automatic backup copies, with re-cycling, to help keep for instance the final 7 daily backup copies and also the last 5 weekly backup copies.