espace gearbox query

[russ hdi]

Hi as title, car wont go into 1 and 2 I disconnected linkages from box and linkage all plays OK.
The shaft behind the passenger wheel will go back to allow 5 and reverse and will sit still to allow 3 and 4 but point blank refuses to move forward to allow 1 and2 like its just not meant to go that way.
Is it seized can it be forced to engage in attempt to free seizing do I need to replace box or can it be repaired, not sure how to proceed really if anyone can help.
2000model grand espace 2.2Dt manual

[lexi]

Is it in the car with oil in it and a running engine. Clutch operating?