Hello Jaki,
I took the liberty of having a look through the Rookwood CD for your Ivy FANTOM but sadly drew a big fat zero

In fact, there was no-one of that surname at all.
Bear in mind, though, that the Rookwood Transcriptions CD contains only transcriptions. It is possible that your Ivy was buried in Rookwood, but has no marker, or that the marker is not inscribed.
There must be a burial index somewhere for Rookwood - can anyone else help with that?
Prue