I'm a descendant of Matthew Marriner (he was my great great great grandfather). My uncle has spent time doing our family history and I'm not sure if the Richard that Polli mentions is the one linked with Matthew. There are similarities - both Richards were born in Yorkshire, both married a local maori girl, both had a son named George.
However, Matthew named a son John apparently after his father - according to a diary entry of the missionary who baptised him (who was the cousin of Matthew's wife). My uncle believes that Richard arrived 3 months before Matthew on the ship James Laing. Richard was given Kataraina who was the daughter of a local chief by whom he lad a son called George who died working logs in 1877. Richard later married her sister Hatariti aged 20 when he was 50.
However, saying all that... my uncle has never been able to find any documentary evidence to link Matthew with a father John. But what he was able to do was link Richard to John. In fact he has been unable to find any birth records for Matthew at all in the UK or his name registered on any of the departing ship lists for the period. What interests me is if it's possible that they weren't brothers, why did they say they were? Were they related at all? Were they just friends and did Matthew have reason to change his name when he arrived in NZ. If you have any info to the contrary proving that they were brothers and Matthew was born in the UK I would love to see it if possible.