V90 drivers seat adjustment
 

I hope this might find someone who can advise. I tried to set the drivers seat forward as I usually do for my wife who is shorted than me. However, when I pushed forward the button (it is electrically controlled) it went so far then stopped short. Normally it would have gone forward another couple of inches. I have thoroughly checked the runners etc for any possible blockage but none.The motor works bag and forward so why has it suddenly started to stop short? Any ideas please? My V90 is the original 1997 version!