Stu supplied the WYAS Highfield reference NI/HI
Within that reference, NI/HI 1/1 is the membership book 1772/1923 (names of members, date of joining, abode (sometimes), date of death (sometimes) and other details such as excommunication, 'defected to baptists' 'gone to America' etc.)
NI/HI 1/2 is the Burial Ground List 1816-56. This is listed in numerical order by number of the grave, and also gives name, age and date of burial.
NI/HI 1/3 is a list of burials 1777-1947, arranged roughly alphabetically, and has columns for 'tombstone number' (NB not grave number), 'born' (only very occasionally filled in),'date of death', 'age', 'relationship', 'occupation' (almost never filled in) 'IMO or orwise' (?) and the last column with no heading, where sometimes an abode is entered.
NI/HI 2/2 is Interments 1871-1981 ('Register of Interments in Highfield Chapel Yard May 20th 1871' is the heading on the first page), and this is arranged in date order, giving name, age, and fees paid for the burial.
regards,
Lesley