It selects all gears and goes into first but sometimes it jumps out of first. I've tried adjusting the clutch cable at the gearbox end but can only get it so far until it gets too difficult to tighten anymore but there does appear to be still plenty of slack in the cable
i had a problem with my gearbox like this lol i tryed every thing appart from making sure who ever changed the clutch last bolsted it up properly i fixed the prob after the gearbox fell off lol i am sure this would not be the prob with yours but maybe worth seeing if everything is sitting right