Someone said a while ago that you can rest somewhere to get woken up by monsters who carry high level scrolls. All I've managed to find is skeletons carrying longswords+1 in Windspear Hills dungeon. Where should I be resting to pick up a laod of scrolls please ?

You're in the right place. Skeleton warriors always drop a helmet and a two-handed sword +1, and then either a piece of jewelery or a scroll. Just be patient. I've found Improved Mantle scrolls, Spell Trigger scrolls... you name it.