Hi a very warm welcome in & thank you, members here are pretty great :)
It would be good to check who your school considers its representative bodies as they may have local organisations they work with.
Board of governors/ school council?
SENCO Social services
Ofsted
HSE - Health & Safety officer
Trade Union representative
ACAS human resources representative
Training & Development officer
https://www.silkysteps.com/forum/showthread.php?t=15168
Page 28 of the workbook that's available on this page may help:
http://www.excellencegateway.org.uk/content/eg523
Best wishes xx