Hi,
I've just been trying to work on the dates. I don't think the Army record has his correct age yet all other details for him are correct. He more than likely lied about his age to take part?
His name is Leonard Reeves, i've attached one of the records for him below for 1915. On another page it says he is 44 and 8 months. The 1911 census I have for him is correct as the same wife is listed along his children all in previous cencuses. In 1911 his age is 46 which is correct as he was born 1865 and like you say the war was from 1914 so on his war record it should state his age as 49.
But although he has children during the war would be adults I can understand them not being listed yet the adopted daughter is listed in the 1911 census so if he was still responsible for her should she be listed.
If you need any more info let know which bits
Thanks,
Hayley