Extensions to coursework deadlines are only granted when your ability to complete coursework has been significantly affected by extenuating circumstances, such as an illness or bereavement. To request an extension, you should contact the relevant course or module coordinator in the first instance as soon as it is possible to do so, and submit a self-certificate documenting the circumstances.
You may be asked to go and see someone at Student Services before the extension is granted. Student Services can inform the School of any adverse situations affecting you, but they cannot request that a School grants an extension.
More information can be found on the University web page here.