Hi Rodney, That's a good idea you have here! I've not seen a list of British Government perfins before.
Here's my attempt at cross-referencing them with my 1998 edition of the Tompkins catalogue.
Any with crowns - not true for the 63 pin crown die of James Russell & Sons Crown Tube Works, Wednesbury, Staffs. (the only die listed just with a crown annd nothing else).
edo - not listed
mhf - not listed
a funny looking "O" open at top - ?
staff and snake - ?
atd - A.T/D - Admiralty Transport Department
ca - CA - Crown Agents (but also Church Army)
cofa - C/of/A - Commonwealth of Australia
dsir - DS/IR - Department of Scientific and Industrial Research
hmf - HM/F - His Majesty's Factores,Gretna, Dumfriesshire (but also a little later the Hotel Metropole, Folkstone).
hmfqf - HM/F/QF - His Majesty's Factory, Queensferry (Chester)
hmow - HM/OW - H M Office of Works
hmso - HM/SO His (or Her) Majesty's Stationery Office
invention - INVENTION (curved) - G F Redfern & Co, Patent Agents, 4 South St, Finsbury EC
no2 - maybe No2/N.F.F - Ministry of Munitions, No. 2 Filling Factory, Aintree, nr Liverpool
nsff - NS/FF - Ministry of Munitions, National Shell Filling Factory, Chilwell, Nottingham
nz - NZ - High Commissioner for New Zealand or Inspector for New Zealnd Dairy Products, St Olaf House, Tooley St, London SE1
ont gov - ONT/GOV - Ontario Government Office, 163 Strand, London WC2
pb - PB - The Petroleum Board (and lots of commercial and local government users)
pto - PT/O - Public Trustee office, London
sdc - SDC or S/DC or SD/C - various local government or commercial users
sds - SDS - The Stamp Distribution Syndicate Ltd, 11 Queen Victoria St, London EC
22 csc - 22/CSC - Cook, Son & Co, 22 St Paul's Churchyard, Lndon EC
18 93 2 style - not listed although 18 on it's own is - London Borough of Sutton
comc - not listed
mhjr - not listed
gjr - not listed
tmchy - not listed
reg off - not listed
Maybe I need a newer catalogue!