Jasp, not sure if this is appropriate in your case, but I've put two springs on the fork seal on another bike that used to be prone to leaking and it extended the life by quite a bit. You simply take the springs out of the old seals and add them to new ones. You best check with someone more knowledgeable first, though.
Oh, and no worries about not having a rear brake caliper on your bike. I never use the rear brake anyway.
