Gearbox Help

Hi,

I have a P reg range rover p38 diesel manual gearbox, was running perfect then one day I cant get reverse or 2nd gear.
Ive stripped the whole centre console, the sound proofing, removed gaitors, I can see inside and the pin well bolt holding the gear lever in place looks worn I want to remove it to check but cant get to lift the housing off as the black metal plate from the gearbox tunnel is there ive loosed it off and removed hand brake but cant lower it or lift it out the way how do you remove it & has anyone else had problems with manual gearbox.

Thanks

i drop whole transmission down a little on a jack ,leave everything connected just lower it