Is it true that taking the lid off to look/stir adds extra cooking time?
Yupp, every time you take the lid off to look/stir, you should add at least 15 mins to the cooking time. The thing with slow cookers is that because they're on so low, it takes quite a while for them to get back up to that accumulated cooking temperature.

Brontide, I'll try and put it up tonight. Not an original, but adapted from an EXTREMELY sweet American recipe (can you say a half CUP of maple syrup?! )