One way to effectively remove bathroom mould is to use a mixture of water and bleach. Using one part water and one part bleach, simply apply the mixture to the affected area and leave for around 15 minutes. Then rinse clean. This can be repeated as many times as needed. Since you are using bleach make sure you use rubber gloves and that your bathroom is well ventilated.
Another option is to purchase cleaning sprays designed specifically to remove mould. They kill the mould instantly and are very easy to use, just spray the affected area and leave for the required time and then rinse with water afterwards. Before use make sure you read the manufacturers guidelines to make sure you use it correctly and safely.