James,
i have this problem. unless my car is at a total standstill i have to fight at times to get it in first gear!! all over gears are fine, and so is my clutch. However when my clutch cable snapped, and i had to replaced it.. i found first gear slipped in fine!! and was perfect for about 2 weeks. Sadly the first gear germlin come back shortly after.
its something to do with the clutch not disengaging correctly... its self adjusting so it makes it a right b*****d of a job. i hear Renault sell a new pedal that was designed to cure this problem, aswell as the consistent clutch cable snapping issue. Should have been a recall, however you know what renault are like in turn charging you £98.00 all in to get it done!!
i just learned to live with it, use 2nd if you drop below 7mph...
it you do find another way of correcting it however.. please let me know.
Cheers
James