I started the bike last week for the first time since November and have noticed a small water leak (weep) from the area in the photo ,it seems to be coming from the bolt above the black tape ,this bolt looks like it might have a copper washer on it .
Well the simple solution would be a dowty washer/seal. I am however wary of water pump seals - bloody land rover seems to eat them. So might be worth seeing what gaskets are in the area.
A simple torquing of the bolt solved mine. If that doesn't work, put on a set of TOR's...the leak may continue, but you'll never be annoyed by the dripping sound.
Undo the bolt, put a solid smear of gasket goo around the head of the bolt and the thread near the head, put the bolt back in and tighten it up. Wipe away any excess goo that is visible. Leak is gone.
As says Gothlander this bolt is for draining the coolant circuit . Just change the cooper washer and tight up at the good torque .
See in workshop manuel