Can recommend staying at Sally's place. It's completely private and you have your own backyard. Very clean and got everything you need. A roughly 20min walk to the Byron town center and less than 10min to the beach (Go to the beach close by and not the Byron main one! Much nicer + not crowded at all).
The apartment is not greatly isolated, you can hear the upstairs neighbours quite a lot. We did not mind, but noise sensitive guests might :)
The communication was great - lovely hosts. I can fully recommend! Thank you for having us!