Gearbox Leaking

Hi, I'm new to this forum so please bear with me. Have had the Laguna for over 4 years and its been great. Now, however, the gearbox is leaking some major oil (mind you, the oil has never been changed in the four years that I have had it but still looks fresh!) ANyway, recently, the gearbox side of the engine dropped (the mounting bolt came undone!). All has been fine since then, but I do think that this is to blame. It is leaking near the inner driveshaft....Am I correct to thing that only the gaitor needs to be replaced (as there is no seal there) or do you reckon there has been some other damage when the mounting bolt came undone?

All fixed now. The seal in front of the gaitor nearest to the gearbox (which apparently holds all the gearbox oil) was damaged (a metal bit). New gaitor (kit) and gearbox oil later all is fine again.