Yes, I'm fine with this line going back, and I already know quite a bit about this family, just not sure of all the Australian descendants - it was a large family - but I do have the marriage and the two children you mentioned.
Lavington Roope's father was: Jonah Lavington Roope, born March 25, 1775, Dartmouth, Devon. Christened 26 April 1775, St. Saviour, Dartmouth. Lieutenant in Devon Militia of Exeter, later became Landing Surveyor for Customs and Excise. Died of typhus 17 June, 1828 in Dartmouth, buried at Dittisham. Married Maria Burghall, dau. of Major Edward Burghall, 1807, St. Pancras Old Parish, London. L. Roope's grandparents were Roope Harris, who changed his name to Roope Harris Roope, and Mary Newman. They were involved in the wine trade with Oporto and the fish trade with Newfoundland.