This might be obvious to most, but it's worth noting that when you fill up the washer bottle, directly below it there are two multi plug/socket connectors just waiting to get drenched in screen fluid. Probably not a good thing to do in the long term..  Not a particularly good bit of design - a bit like the aforementioned bonnet stay slot being upside down. 

Interesting. Can they be taped up for protection?

They are probably well protected and sealed as they are, it's just how they perform after many years. For the sake of the connection being moved a few inches either side during the design stage it seems a bit shortsighted to put it there. I guess it's just a matter of being aware that it's there and being careful when topping up.

Ok, hopefully they'll be ok long term.

I tend to use a funnel anyway so spillage isn't normally a problem.

I always use funnel anyway but good point