Thank you all.
In order to clarify, Owners, like sitters, get notifications/emails ‘you have received a new message’. They can then go onto the website, to read and reply. Once they have reached the 5 application limit, the pop-up appears several times on their dashboard, (ie, if they have dismissed it, logged off and then on again, to read and reply to messages.) It is there as a constant reminder for them to secure a sitter as soon as possible.
I will certainly pass your comments on to our tech team regarding the wording.