Missing Disk Space

Hi all,

I am having an issue with my MacBook Pro's disk space.

I am running a 2013 Macbook Pro Retina 15-inch

Finder, Disk Utility and About my Mac are all reporting that I have 28.5gb out of my maximum 250gb left, but these are not corroborated with third-party tools such as Disk Inventory X (DIX) and OmniDiskSweeper (ODS), they show about 130gb used. (please see attached images)

Since realising I have low disk, I have been aggressively deleting files but to my dismay, my available file size is decreasing from all my file deletion.

I have disabled Time Machine since realising this problem, and had power-cycled my computer multiple times. Carried out extensive google searching and followed many advice given that I will summarise below

Steps I have taken:

1. Disk Utility - First aid (showed some hierachical issues for the first time. Multiple runs thereafter showed no problems)
2. Ran ODS and DIX using root (sudo ODS and sudo DIX)
3. Turned off Time Machine and rebooted the computer
4. Uninstall and deleted a lot of files
5. Rang AppleCare who told me to reinstall my OS.

   This is not an option until the new year's as I am traveling overseas without my physical backup with me

Is there anything else I haven't checked, or does anyone have any solutions to this problem?

Thank you.