squeaky seatbelt

Hi. Wondering if anyone can shed any light how to remove the seat cover on the 2010 Clio rs200. Driver's seat is squeaky because I think one of the metal side supports has come loose and squeeks quite loud. Also the drivers side seatbelt bit that you can move up and down to adjust the shoulder...

My MK2 3dr Clio has a squeaky rear left seat belt that drives both me and my passengers insane! Is there anything I can squirt in there or how would I go about getting access to the mechanism in order to clean and lubricate it? Thanks!