Hi Will,
I was Senior Helideck Fire Officer and HLO at HEMS London from 1992-2000. Although not involved with the initial installation or original build of the helideck I was responsible for the day to day RFFS and Operational requirements, equipment, crewing and training. I also wrote SOPs etc for hospital elevated helidecks and surface level helipad operations (that appear to have been adopted/adapted by several other hospitals over the years).
If I can assist, I now run a business - Helicopter Support Services, specialising in helipad RFFS and ground support services for the UK helicopter industry. I am also the fire training instructor for East & North Herts NHS Trust. If this is the area of enquiry you are looking into you can contact me through the NHS Staff Directory, the NAFHO website or through the British Helicopter Advisory Board site.