The adjustment is at the gearbox end, on the linkage. Put gearlever in neutral, slacken off 17mm nut, position gearlever correctly (preferably get someone to hold it in position) and retighten nut. Some trial and error may be required to get it just right. Something else you should check is the plastic socket that the gearlever itself pivots in, as these are prone to breaking. Remove the gearlever gaiter/surround to do this (pulls off, but can be a bit stubborn!). Ensure that there are no cracks in the white plastic socket, and that the "bell crank" has not migrated to the right; the metal sleeve the crank turns in is a force fit in the plastic socket, and sometimes moves. Good luck!