Hi Danielle,
Here is a good place to start:
Workplace health and safety concerns:
http://www.hse.gov.uk/contact/concerns.htm
Particularly this link:
Check if HSE is the correct enforcing authority
http://www.hse.gov.uk/contact/authority.htm
If HSE is not responsible it tells who is and how to contact the responsible body.
The bit on Whistle blowers is helpful too.
Hope this helps,
Lee
PS: In case you are not aware HSE stands for Health and Safety Executive. It is a government body and part of its responsibility is to check health and safety arrangements are adequate.