Moose, I have found my problems after checking the seating of the rear light clusters. On the battery side, the gasket was squashed and damp in one corner....I looked further down the 'well' and all of the battery area is a block of ice. Will get 2 new gaskets tomorrow and see if leaks still occur.
Other forums told me to look at the seating of the rear screens too, mine appears to be fine. Also, the seating and quality of the boot seal, again mine was fine.
As for your problems, Are you loosing coolant? If so, you may have a minute hole/crack in your heater matrix, especially near where the pipework enters the bulkhead from the engine as this part is plastic....
Also, the wiring loom which enters the car from the engine at one point with a semi-screw-on connection - Is yours seating correctly.
Else, I am stuck on your leak (Which I did have a year ago....now you say that I am gonna have to check mine again).
Good Luck, keep the board posted for future reference,
i
Phil N