Before you can use the SDHS, you must register your use of sensitive personal data with the Information Governance Office and have your study data flows approved, which can be done with the following form:
Once this has been approved, you must apply to use this service here:
http://wwwcscs.medschl.cam.ac.uk/research/informationserver-governanceservices/sdhssecure-onlinedata-applicationhosting-formservice/