Hi,
I found these death registrations
Dec Qu 1961 Dunmow 4a 654 Susan E HALLS aged 85 which ties in with the burial Sue found
Jun Qu 1966 Dunmow 4a 653 Charles E HALLS aged 77
so is this another possible for Charles?
edit, there is a burial for a Charles Edmund HALLS 14 May 1966 aged 76, buried at Takeley Holy TrinityThe 1976 burial Sue found seems to tie in with this GRO registration:
March Qu 1976 Uttlesford 9/3896 Charles Edward HALLS born 16 May 1877 so aged 99

You could contact check with the Chelmsford cemeteries department for their burial records, and you could contact the Chelmsford reg office if you wish to buy the death certs and ask them to check they're the right ones before you buy
The Register Office, 17 Market Road, Chelmsford, CM1 1GF.
Tel: 01245 430700.
E-mail: chelmsford.ro[at]essexcc.gov.uk
may come under Uttlesford District Register Office
The Council Offices
London Road
Saffron Walden
CB11 4ER
Email address: uttlesford.ro[at]essex.gov.uk
Telephone: 01799 510319
Kind regards,
Barbara