gearbox identification

[ross]

Hi, my 2.2dci espace has recently developed a yonking noise when in first and second gear, all other gears are quiet.
My local gearbox specialist says it is the first/second gear shaft bearings that need to be renewed, total gearbox rebuild.
I have been offered a gearbox from a 2.2dci Laguna, but am unsure as to the exact definition for my gearbox compared to the Laguna gearbox.
does anyone know if these gearboxes are the same, or what the differences are, if any.
if it is only some small gear ratio differences I think I can live with that, but if there are some structural differences, I would like to know.
any help or advice will be much appreciated.
Regards......Ross