The Fountain - When and why was it built?

The first question might be, when was this fountain built?  At present I have no records of who designed it,  and when.
As outlined in the history, the gardens were laid out by Sir Richard Wallace in the 1870s, but it was not then that the fountain appeared. The OS map for 1905 clearly shows a circular structure in the position of the present fountain, with a path approaching it from the West, but at this time the area was a  rose garden. The picture below, published in 1901, was taken from a position near the present Italian garden, looking South. You can see a trellis to the west, behind which is a  path leading to a circular rose bed.*

The rose gardens South of the terrace in 1901

By the time the survey for the 1927 OS map was done in 1925, it clearly shows that new steps had been built to link the circular feature to the Italian garden, as well as retaining walls and a new path leading directly to it from where the 1901 picture was taken, and a further structure behind it. Clearly a good deal of money had been spent to highlight this area of the garden, and it is reasonable to suppose that the ornamental fountain was installed as the centrepiece. One might further suppose that such an expensive feature would not have been built after 1914 when the war intervened, after which estate began to decline, and the fountain would most probably date from the years 1909 to 1914, at which point Sir Kenneth Clark was spending money freely on his shooting parties and entertainment.

* Country Life in 1901: "The rose garden is a particularly good one, and lies just below the terrace to the right front of the house, the collection  being a representative one. Many of the beds are devoted to a single variety, such as La France, Marie van Houtte or China roses."   There is no mention of a fountain.