Thanks.

Does anyone know if this sends out from a constant number?

The Telecom eTXT service sends from varying numbers, so they can't be added to a users phone book address, and as such appear to be from random numbers each time.

Looking through here it appears this may be the same on mtxt, but it's not fully clear.

From page 21:

With this system, the SMS recipient may not

know who sent the message so it is suggested

that you add your name and a contact number

so you can be contacted if required (replies by

SMS will go back to your email address but the

person will not be able to call the number that

the SMS appears to come from).