solution
Got my new iPhone 5 yesterday...
however the back up was corrupt so the problem from my iPhone 4 was now on my iPhone 5!
The fix...
All my back up's have always been done in iTunes
This is what I did -
backed up iPhone in iTunes
from iTunes, I un-synced all music/videos
from iPhone I deleted all apps that I did not need the app data for
I was left with about 13 apps (e.g. whatsapp) that I wanted to keep data for
from iPhone went to settings and turned on the iCloud, created an online back up
the first back up can take a hours (6 hours for 3gb for me)
restored iPhone in iTunes to new
restored iPhone from iCloud back up
all my photos, contacts, settings & app data for selected apps was back
camera roll working again! nothing is doubled up
can take pics, vids and save pics into camera roll
turned iCloud off
backed up to iTunes
restored music/vids and apps
Another fix idea -
in iTunes delete ALL backup's
create a new backup
restore iPhone to new
restore from backup
...might work?