I have recieved some more information on the 'other' ORCHARD family that was in the Christchurch area about the same time as 'mine'. Thanks go to a fellow ORCHARD researcher (she is researching the same branch at me).
There was a John ORCHARD and family from Cornwall. He was a minister and they did originally live in the Christchurch area.
As the above was not related she did not follow up on him but it is thought they later drifted northwards to Nelson and surrounding areas.
Following up on minister John ORCHARD and his family may shed some light on John Wallace ORCHARD's family history and explain why I have not been able to connect him to 'my' ORCHARD's. It could also be that Sidney Arthur ORCHARD could be a part of the same family as I have no connections for him in my family either.