If you wish to enrol on a course of study (part-time or full-time) this is possible on any Dependant visa. However, you need to be aware of the risks and restrictions of doing so which are as follows:
You need to be aware that should your circumstances change (for example, your visa expires and it is not possible to extend it, or the person to whom your visa is tied is no longer in the UK, or your relationship breaks down and you no longer have the right to remain in the UK as a 'Dependant') then it will a) not be possible to switch to a Student visa from within the UK, and b) not be possible to apply for a Student visa, from outside the UK if the course you are studying is is 'part-time'. The University cannot issue a CAS to a part time student in order to make a Student Route application. Please do be aware of these restrictions when making the decision to enrol with a visa in the Dependant category.