Are you adding waste from animal bedding? Or are you adding too much soft green waste (such as grass cuttings)? If so try mixing the contents more with prunings, shredded paper, leaves or straw which has been chopped.

Hi Ninja,
Try posting your plant question again with a photo. Cytisus is not something I'm familiar with, but you should get more of a response, and more accurate.

On the compost bin part of your question, the simplest solution to 'sweetening' your bin is to get some garden lime and shake a few handfuls of that in when you add waste, especially grass cuttings. Not only will it smell better but it will help the composting process work better. The best stuff of all to use is calcified seaweed, but I'm too much of a skinflint to use that.

Thanks for answers, I will try the garden lime thing Bertiefox, never heard of it before but it sounds promising!