I've just come across the papers of Bdr. Thomas NICHOLS, L/34690 RFA (via The Ogilby Muster) who gives a very good description of life at the Havre base. He also lists the separate camps that made up the base when he was there in February and March 1917 - https://www.theogilbymuster.com/record/2484322.

No. 1 Camp = Guards Depot
No. 2 Camp = K.R.R. and R.B. (later occupied by R.G.A. Siege Batteries)
No. 3 Camp = K.R.R. and R.B.
No. 4 Camp = K.R.R. and R.B.
No. 5 Camp = R.G.A. Heavies
No. 6 Camp = R.G.A. Siege
No. 7 Camp = Medical Board Quarters - Motor Ambulances
No. 8 Camp = Army Service Corps Depot
No. 9 Camp = Army Veterinary Hospital
No. 10 Camp = Artillery Training School
No. 11 Camp = R.H. & R.F.A. Signals and 4.5" Howitzers 
No. 12 Camp = R.G.A. Reinforcements
No. 13 Camp = R.H. & R.F.A. Reinforcements
No. 14 Camp = R.H. & R.F.A. Overflow
No. 15 Camp = 46th & 56th London Territorials (Reinforcements) - I think he means 47th here
No. 16 Camp = No. 1 Medical Board Base Depot
No. 17 Camp = Irish Regiments (Reinforcements) - later Labour Corps
No. 18 Camp = 36th Ulster Division Training Depot and Base
Additional Camps were:
No. 19 Camp = 36th Ulster Division Reinforcements - later Q.M.W.A.A.C. 
No. 20 Camp = Australian Infantry Corps
No. 21 Camp = Australian Infantry Corps
No. 22 Camp = Australian Artillery Reinforcements
No. 23 Camp = Infantry Training School

Among the various institutions were the following:
Expeditionary Force Canteens - 6 in all. Each supplied Beer, Food and all sundries required by troops.
Catholic Club Hut - One of the most popular canteens and rest huts.
The Salvation Army Huts (12 Camp) - Plenty to buy. Dirty Tables. Plenty of paper and envelopes. Services and a fine band.
Woodbine Hut (Y.M.C.A.) - Excellent concerts and sing-songs, reading and recreation.
Y.M.C.A. - The largest in the base
Wesleyan Hut (15 Camp) - next to Cinema - good refreshments and billiards.
Guards Institute - Open to only NCOs of other units and Guards.
British Red Cross - Recreation and services.
There were 2 Cinemas in 15 & 17 Camps.