I am trying to replace the moulded carpet in a 1992 MK2 Panda 1000L. I've removed the back seats without any problems, however I got stuck with the front seats . There are two plastic bits fitted to the front end of each rail. It appears that each front seat would come off the rails by sliding it backwards following removal of all of the 4 plastic bits. Am I right? How do I remove the plastic bits without damaging them?