My property suffers from mould. Is it my responsibility to clean it?

If your property is suffering from mould, you should clean it away, regardless of responsibility as it could be a detriment to your health otherwise. If the cause of mould has been found to be through condensation, then this would be your responsibility and you'll need to ensure that this is not only cleaned away but any other damage which may have been caused to the property as result, such as painting if rectified as well.