Steering box leak/squeeking

Got a squeeking coming from the front end on Friday and had a look this morning and the steering box seems to be leaking quite badly as is the damper coming off it. Never had any experience with this and was wondering how hard a job it is and if the whole box needs to come out or if it can be done in situ.
2001 defender 90 td5

seal can be done insitu if you can get drop arm off and shaft is not pitted were seal runs