I have no intention of renouncing it unless push came to shove but apparently you don't need to renounce. As Thai society is built on a charade showing intent to renounce is obviously one of those sharades that I must go through.
I contacted the Thai Consulate in bbk who said contact the department of home affairs in Australia, so it's obviously going to lead down a rabbit hole unless someone who has done it reads this post and replies.