2005 transit sliding door

[Chriscp9be]

Good morning
I have bought a 55 plate transit and having sliding door issues
I have exposed the cables etc and notice the cable from the outside handle to the mechanism doesn't seem to return properly
I can open and close the door fine from inside but if I open it from the outside the cable doesn't return/is a bit stiff and the door won't close unless I manuall push the cable back?
Could this be a stiff cable or another issue?
Many thanks in advance