From Andrew from Dolton in Cooperi comments:
I would like very much to find out more information about a garden in Haywards Heath called Earldom (as in the rose 'Earldomensis' a pteracantha hybrid). My parents lived in the town over thirty years and I grew-up there. It was from 1915 (I think) until just after his death in 1948 the home of The Royal National Rose Society's rose garden and trial ground and the private home of Mr Courtney Page and his wife, members since 1892. Situated on the Lewes Road in Haywards Heath. I still have relatives in the town and often go back and have unsuccessfully looked for the house on several occasions. One of the most expensive roads in town with many substantial houses and big gardens, I guess that name may have been changed during the last 70 years. I contacted the local horticultural society but they couldn't help and now the R.N.R.S. is defunct I have come to a dead end.

Andrew - do you have any at all of The Rose Annuals?
I think you are referring to Site No [1] below? They are my [parenthesis].

From the 1976 Annual, page 63:
The first Trial Ground of the National Rose Society was at Haywards Heath attached to the private garden [1] of Mr. And Mrs. Courtney Page. The head gardener was Mr. Baines who probably knows more about the many vicissitudes of the Society than any one else. Mr. And Mrs. Courtney Page were married on September 3, 1892 and decided on their wedding day to join the Society. She soon became influential in organizing the first Queen Alexandra Rose Day and he became Secretary of the Society in 1915 and joint Editor of the Annual in 1917. (The first Annual was in 1907). Mr. Courtney Page died in 1947. He had been in failing health for some years during which all work had been efficiently carried on by Mr. Harry Edland who, with Mr. Baines in charge of the roses, piloted the transfer of the Trial Ground to two acres of land [2] loaned by the Hertfordshire Institute of Agriculture. After three years the area was needed by the County and another site [3] was offered. Even though it was probably that this site must soon become inadequate, Memorioral Gates were erected and dedicated to the memory of Courtney Page 1915-1947. During all this time the offices for the ever increasing amount of secretarial work were first at 28 Victoria Street and then at the poky little third floor flat of 117 Victoria street, Westminster....

From the 1948 Annual, page 11: The Late Courtney Page. (Includes photo) .....Except on a few special occasions, the hundreds of articles which he contributed to The Rose Annual never bore his signature, but were anonymous.

I have found a couple of photos of him and perhaps a search of 'Earldomensis', [later edit - it didn't] and a quick skimming read of the old Annuals might also bring some information. But I have to go out and will not be able to get back to the books for another two days. Perhaps other English members may also be able to contribute in the meantime.