The Office for Nuclear Regulation (ONR) has an agreement with the Health and Safety Executive (HSE) for handling its ICT systems, but HSE does not hold separate details for ONR. Therefore, the details provided are for HSE as a whole, including ONR.
Personal information such as names and email addresses have not been provided under the exemption in Section 40 (personal information) of FOIA. This is an absolute exemption, so is not subject to a public interest test.
FoIA Section 40 - Personal information.