Here is a copy of one I have used, it's very old and was geared towards parent to child but you can just leave out or change those bits to suit. Mine is actually from me to my father so other way around.
The second ones are copy of a revenue brochure which also has the wording attached, again very old 2004, they may have an updated one, the brochure is on their site but it doesn't show the form so not sure whether or not there is a form attached to their newer brochure.
You could just retype it out with similar wording. The bit at the bottom about tax districts etc is obsolete now I think.