Hi Ros - been checking and looks like those extra three do belong - would match the death certificate of the James snr.
Also it appears that the first 4 children were all under Morris ( Names, DOB, places, baptism records concur where the next appear to be Morrison but Mum still Eliza. Rest have Morrison and Elizabeth.
Have requested a few copies NSW BDM so hopefully these will prove that James Morrison is James Morris and confirm marriage.

Thanks so much for your help everyone.
Neil - you were right - one set of twins were not twins- have found correct DOB under Morris for that child
