I wasn't aware that a window was available
When viewing the battery when standing at the front of the car, the battery, which is housed in a black coloured housing, is located right-hand-side and to the rear. If you look carefully at the left-hand-side of this black housing there should be a slot cut out of it roughly an inch in width allowing you to see both the min and max markings. With that said, as indicated in my first post though, actually seeing the electrolyte level is another thing altogether and from my point of view anyway, physically unscrewing all the caps and checking there are no exposed (dry) plates is the only way to be actually sure.
I think as far as claims go it one would be very much in the hands of the dealer with fingers crossed for a 'good one' as an argument could be presented that any failure is down to user neglect and/or the battery is a consumable item.