Got the seal replaced today, after you get the front wheel off, it's only about 30 minutes of work.
Four screws hold the front fender on, one bolt secures a brake line bracket to the lower fork tube, two allen head bolts that secure the lower fork tube to a brace that connects the two forks together.
Then just pull the lower fork tube out, the inner tube stays in the triple clamp.
Remove a wire circlip, that has two ears bent into it, so it's easy to remove, pry out the old seal, and then back together again.
The fork holds 470 ml of fork oil, its just to lubricate the parts, there is no damping action done in there.
From what I've been told that it is common to have the left fork seal leak, it has something to do if you leave the bike on the side stand with the fork locked, it puts a side load on the fork seal and flattens it slightly, causing a leak.