Ian
Here are some useful books:
'Haig's Generals' - edited by Ian F.W Beckett and Steven J.Corvi - first published in 2006 ISBN 1 84415 169 7. An excellent book with a chapter on each of the following: Allenby, Birdwood, Byng, Gough, Horne, Monro, Plumer, Rawlinson, Smith Dorrien.
'The Great War Generals on the Western Front 1914-18' by Robin Neillands first published in 1999. ISBN 1-85487 900 6.
'Command in the Royal Naval Division - A Military Biography of Brigadier General A.M.Asquith DSO,' first published in 1999. ISBN 1 86227 048 1.
It depends how detailed you want to get but to gain a better appreciation of the man and his staff then the opportunity also presents to examine correspondence in books such as:
'Allenby in Palestine - The Middle East Correspondence of FM Viscount Allenby' by Matthew Hughes - published in 2004 ISBN 0 7509 3841 2 for the Army Records Society.
'The Military Correspondence of FM Sir Henry Wilson 1918-22' likewise that of 'FM Sir William Robertson 1915-18 ' for the Army Records Society.
The more extensively one reads one's chosen subject then one gains a far wider appreciation, acknowledging that history is littered with differences of opinion.
For further details see
www.armyrecordssociety.org.uk
Philip