My "other" partition was up to 25G!!!! I didn't want to restore my phone as I would loose important SMS and info on it.
I found this link and followed the steps
Using that program suggested was free as I did it straight away after downloading it. I removed my files in
"media Folder" the following files
- music - all the "F" files
- ApplicationArchives - all the big stuff
- Recordings - all currupt M4a in there
Vola! My phone now has 25GB back!!!!!
Hope that helps