Flat battery

Hi Guys.

I went into my garage yesterday, to find my car door slightly ajar, and with a flat battery due to the interior light being on for a week or so.

The battery is a sealed type, about four years old.

I do very low Kms a year, about 2000, as I walk to work.

I've had it on the battery charger overnight, and I'm about to put the battery back in the car.

My question is, is the battery now stuffed?

Are sealed batteries more robust than the wet type that you put water in?

Any replies would be much appreciated.


Cheers

dino