Hi @KarenDeAnne another Aussie sitter & home owner here from Brissie.
Most sitters apply for multiple sits for the same or similar dates. When you confirm a sit you then withdraw your applications for the others with a short note to the owner saying you are now no longer available to do their sit. Some owners are slow to reply/decide on a sitter. In this environment of more sits than available sitters (particularly in the UK), it’s a matter of you snooze, you loose for tardy owners.
Please make use of the spy glass above to search the forum for your question as there is a wealth of information available for new members. Here’s one of many threads about your question.
You will find the experienced members on here are very supportive. If you can’t find your answer through the spy glass search, ask away.
Hope you have a great UK/Europe trip. I’ve done 5 month and a 3 month trips sitting in the UK which were fabulous adventures.