Kia Ora Hazel,
Anyone interested in the Alexander family in Tasmania and Ramsbury, Wiltshire, may find some useful information, together with some family tree details, in the following book;
Frederick Matthias Alexander: a family history by J A Evans, published by Phillimore & Co Ltd. ISBN 1 86077 178 5.
For information on the Alexander Technique, google STAT (Society of Teachers of the Alexander Technique)
PS There is a significant branch of the Alexander family in NZ