Welcome to the forum.
In the Project Panel, you can edit your Columns. I move Video & Audio Usage to the front, right after Type. It will give you a count of the times used, and display a 0, when not used. PrPro will also allow you to Remove Unused from the Project.
Now, as PrPro does nothing at the system level, you might need to go in reverse - make note of the Assets Used, and then manually Delete the Unused.
In the Project Panel, click the flyout menu; that's the little stack o' pancakes thing in the upper right corner of the panel. Select "Metadata Display." In the search box, type "usage"--this will reveal the Video Usage and Audio Usage metadata labels. Check those to add them, and hit OK; they'll now be added to the columns in the Project Panel. Now, you can sort on those columns to filter by usage--the unused clips won't have a number associated with that column. Select them all, and if you really want to purge them from the drive, hit Ctrl/Cmd+Delete--that will remove the media from the drive.
If you just want to get rid of the clips, Project > Remove Unused will do that.
thank you thats great. Do you know of any way to indetify the files (without deleteing the unused) in the timeline so that i can transcode only the ones in the timeline. As far as im aware this is proxy editing though i haven't been able to work it out properly
You could create a new project, and import your original project into it. When you do so, you'll get a dialog that will ask if you want to import all sequences or just select ones; pick the sequence that you want to transcode/consolidate. That will import just that sequence and its connected media.
You could also run the Project Manager (under the Project menu); this will let you select the sequence(s) you want and then copy the media to a new location. Again, you'll have a new project and it will connect to the copied media. You can transcode those, then, and work from there.