Alfred DENYER (no middle name) to:-Mary Jane WALDER June quater 1895 vol 2B page 399, this looks more like the marriage of your great grandparents. This also fits with Victoria's name.
FindMyPast has transcription of this marriage. It took place on 25 Apr 1895 at Hurstpierpoint. Alfred's father was called Nathan. Alfred Denyer was 22 at marriage, so born approx 1875.
The 1881 census has the family at Hangleton. Nathan and wife Jane with several children. Nathan was born in Wisborough green, Sussex approx 1837.
The other Alfred (Alfred Jupp Denyer) was born in Sutton, Sussex approx 1864. In 1871, he's a pupil at the workhouse in the parish of Wisborough Green.
Familysearch has his baptism on 24 April 1864 at Sutton. mother Fanny Denyer, no father mentioned, but from his name, it might possibly be a Mr Jupp. The record says residence was West Thorney, Sussex.
There are a number of Fanny / Frances Denyers who are possibilities for the mother on various censuses, but none connects to Nathan.