From Sarah Harris, author:
Basically the answer to our shipping issue is that Amazon UK has no stock as their stock comes from Australia and is not being sent because it is non-essential.
Amazon US apparently is always later with Australian titles and it will not be available until January 2021.
Booktopia does not send overseas only within Australia and NZ.
The options are Book Depository – and publisher warns there could be long delivery delays in spite of what they say on their site. But if people are patient they can get hard copy that way.
Or the ebook, which is available for immediate download on ebooks.com or Amazon.