I've just found black mould on the back wall of our biggest kitchen cupboard. It's where the stopcock is so there isnt a back panel, just the back wall, which is an outside wall. We do have issues with mould on the inside of the external walls. We have to be careful with ventilation etc and I'm pretty on it now.
I've cleaned it up the best I can but access is difficult. Can I still use it? Its the biggest cupboard by far and our kitchen is pretty small. (It's one of those annoying corner ones)
I figured tins and sealed packets should be ok as long as theyre not close to the wall, but could I put pans in there? I really don't want to lose that space completely but I don't want to make us ill either 
I'm going to get one of those mini dehumidifier things to put in there as well.