Peter,
Absolutely right all Military cemeteries are now one and moved to Kranji CWGC Cemetery, Singapore, where I was commemorating the two 2 PARA lads killed at the Battle of Plaman Mapu two years ago.
As always the CWGC have done a very moving job ther bringing all the graves together in one place on a hill overlooking the harbour. I know the Cemetery Supervisor there and his team of 12 workers, amazing what they do in that intense heat on a daily basis. He is shown on the left of the attached photo. I am taking the pics.
In answer to your specific question the Imperial War Graves Commission (IWGC) was founded by a Royal Charter in May 1917 to provide for remembrance in perpetuity as graves massed during WW1.
However, in March of 1960, as Britainwithdrew from its massive Empire, its name was changed to the Commonwealth War Graves Commission (CWGC)
Second photo me standing with the PARA RHQ Wreath with Lt General James Bashall ex 2 PARA CO