Did you backup the catalog prior to sync process?
Sync process removes missing files from the catalog and not the normal ones.
Did you land up in any other catalog by any chance?
Go to File menu > Open Recent Catalog > check if it lists there.
I'm curious to find out exactly what you did.
Some of the terms you use don't make sense with Lightroom like:
"I am currently editing a large lightroom CC file and i have placed it into a folder." - what exactly are you doing here and how???
"The last action i performed was to sync all the photos into a 1920 x 1080 dimensions." - what is this??? were you cropping or exporting or what??? How did you "sync" to a dimension???
Backup not done unfortunately. Got carried away, Im assuming they are wiped? If so why not any others folders?
They are not in any other Catalogue and i have tried File Menu etc. Its not there either.'
Sorry for the confusion. I placed the edited photos into a 'folder' rather than a 'catalogue'.
I was cropping the photos via Develop -Crop - Aspect- from here there is a little key and the dimensions can be changed. After changing one photo I highlighted all the photos and Synced all of them....effectively making all of them 1920 x1080. During this process the photos started to disappear and the folder displayed a zero content. I was thinking is there a size limit? There were approx 1300 photos in the folder....