Replacement gearbox?

The syncro has gone on the second gear I think of my 90 200tdi and while I have got used to the adapted gear change up and down into it, would be nice to not have to do it. Is this a replacement gearbox(reconditioned) or can this be fixed at a fraction of the price that I'm getting quoted for box fitted?

depends on wheher its h suffix (last letter on serial no) or g ,g could be replaced for £100 if you can find some one who does them , h depends on how much needs replacing

Thanks, Where abouts would I find the serial number on the gearbox?

Found where it should be, will take a look