a bung?!
Ours have these silly grommet things that seem to be there to funnel the water away but i'm sure they add to the blocking-up-ness
diesel: if you haven't cleared the drain behind the servo you really should try to clear it out, if you take the battery tray out, you can just about squeeze your arm along behind the servo and poke at the hole to clear out the silt thats blocking it. If the two of them are clear, it means you'll have a bit longer before having to take it all apart and clear it out again.