The GUM Examinations
There are several mandatory courses and qualifications which are laid out in the JRCPTB GUM 'blueprint'. 

These include the diploma in GU Medicine (two sittings/yr). Recommended to be completed during ST4), the DFSRH (online and practical training)(during ST5), and the DipHIV which equates to an exit exam and should be taken during ST6 (two sittings/yr).