My lovely megane ('53reg Megane ST, 1.9DCI,expression, manual) developed yet another problem

Has anyone else had problems with their driver jamming? it was fine until this morning when I got in and wanted to knock the seat back a notch, but it wouldn't go. I tried forwards - no joy.
There was no 'twang' like something snapping, or rattling like something has come undone.
Any ideas??