Dolphin Chapel is the old Clayton Heights Wesleyan Methodist Chapel at Dolphin in Shelf. Address is Chapel Lane, off Highgate Road, Clayton Heights. Taken from Bradford Family History Society's CD "Great Horton Methodist Circuit transcription of Burial records & MIs". I think the Tordoffs founded the chapel and they had a significant presence in Wibsey Moorside. Indeed there looks to be a William Hardy illeg son of Ruth Tordoff, so these families obviously lived cheek by jowl.
You're right there's no indication of her being a minor upon marriage - she's called a spinster. But her burial record gives her age and I have to give that great weight. Anyway, her husband was under 21 and he isn't recorded as a minor. I have seen the term "spinster of a minor age" being used, so being a spinster doesn't necessarily preclude one being a minor.
The business of whether a marriage is Bradford or Halifax is not clear cut. The Bottomley family moved from Bradford parish to Halifax parish a little before 1796. But they lived in cottages at Soaper Lane Bottom which even today straddles Blackshaw Beck. One side is in Wibsey (Bradford) and the other side is in Shelf (Halifax). So a move of a few feet changes the parish. John Bottomley was almost certainly still with his parents, so was in Shelf, so his marriage to Sally Hardy is a bit more likely that to Sally Hague. Being in Shelf didn't prevent the Bottomleys using Dolphin Chapel - and in fact various family groups popped back and forth over the Beck from time to time. They had something like seven or eight cottages in all, mostly one-roomers, nearly all on the Wibsey side.
I now know the Hardy's two youngest children both died in 1791, buried in Wibsey Chapel. But then there's silence. I've also found their MI. There's no reason they hadn't crossed the Beck into Shelf by 1796.
There are no baptismal records for any of the eight children of John & Sally Bottomley, bar one: Nancy, recorded born in Shelf (in reality, Soaper Lane Bottom) and baptised in Bradford Parish Church. All the surviving children record in the censuses they were born in Shelf (although once or twice they forget/get confused and put down N Bierley). By 1814, the family were back in N Bierley; the two youngest, who died in infancy in 1814, were apparently born there - but even here confusion reigns - on one burial record the father is "John Bottomley Shelf of the Parish of Bradford". In 1822 he was bequeathed the cottage he was living in - in "Sooper Lane, Wibsey" so at least we know which side of the Beck he was living on then.
But when he died in 1847, his death registration states he lived at Revo, N Bierley, but his burial in Dolphin records him as living in Shelf. Never was meant to be simple, was it?!