This code system https://fhir.yhcr.nhs.uk/CodeSystem/Interweave-SocialCareRequesterType-1 defines the following codes:

CodeDisplay
ADV Advocate
ANON Anonymous
ASCP Adult Social Care Provider
FFN Family/Friend/Neighbour
ICC Integrated Care Centre
IC Intermediate Care
INT Internal
LAHD LA Housing Department/Association
LA Legal Agency (Police, Court, Probation etc)
MA Managing Authority
UKN Not Known
P Portal
PCH Primary Community Health (GP, community based)
SH Secondary Health (A&E, Hospital, OT, Ward, Hospice)
TA Trusted Assessor
OTH Other
S Self