Windscreen wiper help

Hi All,
New to the land rover community.
I've hit my first Defender problem and hoped someone could enlighten me with a solution. The windscreen wipers on my 2008 110 seem to swipe right but not return to the home position, this is currently solved by using a stick I keep on the passenger seat to give the wipers a budge. When stuck I can hear a whirring motor noise. I lifted the wipers off the windscreen to see if they would go back and forth but they again got stuck in the right position. Not quite sure what needs oiling or replacing.

Any help would be greatly appreciated
Thanks

William

In order of likelyness..
Spindle adaptors
Wheel boxes
Drive cable
Motor gear

Hi Flossie,
Sorry for the late reply, took me a while to get cracking on it. I replaced the spindle adapters and drive cable (Holy crap, a puma dash takes ages to dismantle). Seems to have fixed the issue, I'm hoping I won't have to get behind the dash again.
Thanks for the help

William