Ok so I gave in, mate bought another gearbox, because the add said "genuine Honda" it came wrapped an old blower box, so my suspicions were raised immediately and then when I discovered the 2 holes that hold the shifter cable bracket on had not been tapped, pretty much a dead give away that Mr Honda had not put his stamp of approval on it. Anyway I have fitted it and we will see how long this one lasts. I split the old box but I wasn't able to see any visible damage. I have a feeling that the drive pinion may be the cause, not meshing with the crown wheel enough. Not enough time or interest to be bothered putting it back together
