If you have concerns about a candidate's fitness to practise you should follow the advice at paragraph 25 of Medical practice.
Spring v Guardian Assurance plc and others . The principles in Spring v Guardian Assurance have been found, by extension, to apply to statements made or information provided after the employee has taken up his or her new position (McKie v Swindon College  EWHC 469).
Kidd v Axa Equity & Law Life Assurance Society plc, Allied Dunbar Assurance plc 
This includes your views about a colleague’s age, colour, culture, disability, ethnic or national origin, gender, lifestyle, marital or parental status, race, religion or beliefs, sex, sexual orientation or socio-economic status.
Saha v Communitybaptistpa  EWHC 1907
You should also consider the impact of the data protection law on the disclosure of special category data. Further advice can be sought from the Information Commissioner.
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