210 Ball diff??
 

Just taken mine out an turned it left/right an feels a little notchy it's not loose or unusual movement also it's a bit stiff to turn is this normal?

How old is it?
It may be time to flip the plates and get new balls.
Did you run it in and only have it as tight as you need, not tighter?
Or
Sometimes you can get away with just a good clean and new grease with a bit of a run in again.

to be honest someone told me to tighten it right down an then back it off a 1/4 of a turn?? Also its about 4 month old

Ouch. That'll probably be knackered then! You've probably put flat spots on the bearings, or dimples in the plates......

Get some new balls and flip the plates (unless you glued them in place, then you'll need new ones!) and read the Durango build guide as you go.
http://www.team-durango.com/blog/201...ild-guide-pt1/

With bearings like that, its (technically) better to be too loose, have a bit of slip, then tighten them up, than start off too tight and brinell the bearing races.