John Tann Reliance Safe - Opening procedure / tips, tricks and information

[Pseudoscope]

Hi All

I'm recently acquired a John Tann Reliance safe (QLD, Australia) along with it's keys(?). The problem is the people who I got the safe off can't remember the last time it was opened and the safe has been partially flooded so things are a little seized up.

I've attached some images, I received 2 different keys, The one that fits the safe is marked "J Tann, Patent" on one side and "reliance lock" on the other, the other (with the ribbon attached) has John Tann Ltd London stamped on the key and I assume is for something internal.

The safe has 2 key holes, one with a post (no. 1) (that I don't have a key that fits) and one without (no. 2) . The one without, no.2 is located on the bottom and initially the key wouldn't fit, but after inspecting with an inspection camera and aligning the tumbler(?) the key now goes in and turns anticlockwise just over half a turn. With no resistance or indication that any is happening inside the lock, with resistance much like a combination lock

My question is, how do I open this safe? Is it only one key to open it? Which way should the key turn, how much? After getting the key to the right position which way do I turn the handle and how much? (it currently doesn't turn)

What methods would you go through trying to troubleshoot the safe?

Regards,
Pseudo