Had a puncture last week (NSF) which was replaced right away but yesterday noticed shedloads of what can only be gearbox oil all over my nearside wishbone. As far as I can tell it seems like its coming from the front diff. So unfortunately I think the oil seal has gone.
What do I need to fix this? Is it something that I can do myself? If I get a garage to repair it, will it need to be a specialist and do I need to source any special parts? What would the repair likely cost?
Lots of questions I know.... sorry!...
I called the AA and they did sweet FA to help, saying that its not drivable and is dangerous.

There isn't any funny noises at the moment so I don't think any serious harm has been done but not going to drive the van until its sorted.
I have a long drive to Switzerland in 2 weeks so really worried that its not going to be sorted in time, especially if it have to use my spending money to fix the van

Any help appreciated guys...
Luke