Google Sheets, random text cell from column, but not used in last 7 selections

I have a Google sheet where I am pulling in the weather from a BBC RSS feed. (weather tab). I am then extracting the current brief weather synopsis from the title, so 'Sunny' for example.

I want to have 10 or so messages (Select Tab) in a column labelled 'Sunny' (there's Rain, Cloudy and others too) where a random cell is selected based on today's weather, and then sent to the 'Todays Message' sheet So I need to say basically. If Weather!A5 = :Sunny, then select a random message from !Select A:A (but not that's been used in the last 7 times) and paste a copy to !Todays_Message A5.

I hope that makes some kind of sense?

Here's the sheet and it's opened up for editing: Google Sheet Test

Thanks in advance