Leaking swivels is a hot topic on land rovers, and general swivel related topics is something I am more or less and expert on these days.
Judging by the road dirt, I'm guessing you don't off road.
That is a major consideration which drastically alters my advice for some people.
Anyway, general rules of thumb, if the balls are pitted, they will leak.
Moreover, if the balls are pitted they will damage new seals aswell so you will have leaks and more leaks.
The easy option is to replace the balls with new Teflon units, they are not as strong or hard wearing as original chrome balls which tend to last 10 years or more but you will get a couple of years out of them
You could try swivel ball gaitors, they prevent stone chipping but I assume would trap water, these are only suitable for road cars IMO.
Anyway, a full swivel refurb inc new balls and seals will see you right, do both sides for completeness.
There are further options, firstly consider running ep90 in the swivels not grease, it is better for your cv joints and leaks more easily so let's you know sooner when your swivels are LETTING WATER IN (guess what, grease doesn't tell you that)
Then there is the stage 2 upgrade (back to old fashioned land rover setup) of converting to oil in hubs also, again, better for bearings and no dry fretted drive flanges or ruined CV joints anymore.
Plenty of advice available here so chin scratch to your heart's content.
. Whilst these I saw something dripping onto the front wheel 
