I think it is 2 nights/3 days for silver and 3nights/4days for gold, that was how I understand it.
Has anyone done an exploration. Our leader was explaining that if you don't feel up to doing a really long walk like for gold and that you could do an exploration. This is where you camp in one place and walk out from that place each day and look at the landscape so one day you could walk out in heading to a mountain, go up it and draw the landscape. However on the next day you walk out and study something about a river for example. By doing an exploration you don't need to carry as much kit with you as you only need a day bag for the walks and you can leave your clothes and tent on the site so you aren't laden down with kit.