Extract from the HMSO pamphlet:
Histories of the First and Second World Wars, revised to September 1969
As it only includes odds and sods of the First World War histories, these have been excised.
Being a 1969 list, it's also missing the volumes published after this date. This includes the back end of the Italian Campaign and those connected to still-secret aspects. However, you may find the synopses of use.
New Resource UK Official Histories of the Second World War 1969
HMSO List of Official Histories