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You night try Pine straw instead of wood mulch. It's less prone to washing.
I suggest you get the security company who monitors the system to repair it. They can tell you whether the electricians caused the damage. If so, send the bill to the electricians. In general, they should be responsible for damage they caused. In certain cases, it could fall under exclusion in the fine print of their quote or other printed materials you should reasonably have been expected to know about. If the wiring was a hidden condition or they had no knowledge it was there, they may not owe you for it. In that case, their desire for your good will might still recover it for you.
This is a spot where cracks often develop. After cleaning with a a mildewcide, check carefully for a crack. If the grout is cracked, open the crack up a little wider with a grout saw (inexpensive at a hardware store) or steel blade and fill it with a color matched caulk or sanded sealer from the tile store. If the crack has moisture, let it dry well before caulking.
Karen, I'm not a painting specialist, but from my experience you would be better off with a good coat of oil based primer. First, sand thoroughly, including the details, then wipe clean with a tack cloth or lint-free rag dampened with solvent.
Consumer Reports Sept 2010 rated Gutterglove Pro the best overall. It does indeed stop everything from getting into the gutter. Gutterglove recommends using an inverse mounted brush on an extension pole (supplied) to sweep off areas with unusual buildup as required. In my experience the need is rare.