I'm only very distantly related to the GURR family through George (1789-1874) and his first wife Keturah (YOUNG). Your Grandmother is related to George through his second wife Ann (ALLCHIN).
Mary Roberts (1819-1913) was a sister to my g-g-grandfather Robert Roberts and came to SA separtely in 1850 aboard the ship HYDASPES as a companion to a 'Mrs Gurr and child' and while I have found who she married - one Joseph GURR, son of George and Keturah - and have traced her descendants, I'd like to find out who this 'Mrs Gurr and child were.
Most of the extra information I have on the GURR family is as a result of my curiosty. They appear to have come out to SA at different times and while I have most of the names sorted into their correct boxes I have a couple to put together to finish the jigsaw puzzle.
When I have them all pasted together I'll be pleased to let you what I have found.