Repair/replace drivers seatbelt L322 2011

Hi Chaps ...my 'New 2011 TDV8 4.4 drivers seat belt spring has lost it's mojo ...just won't spring back up 9 times out of 10 ...however it's not that old , so maybe just needs a lube e.g. wd40 , KY jelly ?..or replace. Any good vids on
YouTube etc. ??? To describe access method ?
Cheers
Scott.