Private companies who provide services to the NHS also get @nhs.net email addresses. It's a secure email system so that patient and other confidential data can be exchanged between providers without it going out onto random internet mail servers.
An @nhs.net email doesn't mean "this person/organisation is a part of the NHS", it means they provide services to the NHS and need to deal with patient data.
An @nhs.net email doesn't mean "this person/organisation is a part of the NHS", it means they provide services to the NHS and need to deal with patient data.