@Sam93 , Here is another topic that discusses this.
https://forum.trustedhousesitters.com/t/when-owners-don-t-write-review/
The THS site will cue the HO to write a review if they log on but chances are, they may not until they’re ready to list new dates. Have you sent a review request? You can do this by clicking on your profile, then reviews. You can also send a private text to them. If no results after two weeks, I send a third request. If no results after that, it’s a washout, unfortunately. Sometimes after a long time an owner will surprise you and leave one.
I now only leave feedback after the HO has left me a review. They need good feedback to make their listing attractive to prospective sitters, and a sitter who has received a review is more likely to leave feedback for the HO.