Mail App Issues

Hi!

It's been a few years since I last owned a Mac, recently picked up a new MBA and have been loving it. Unfortunately I seem to have a small problem with the standard Mail app on Mavericks - something I used to love with OSX was how well the standard Mail app worked with Gmail but something has changed.

New mails download fine and I can send mails fine with no problems, but when moving my messages to "All Mail" (Similar to Archive on the web interface) the web interface doesn't reflect this and nor do my other iOS devices.

I made a short video showing exactly what happens, you'll see when I move the email from eBay confirming a listing it moves successfully but after refreshing the web interface it comes back. I then move all messages but the web interface doesn't show this. You can view the video here : https://www.youtube.com/watch?v=nHo-r6vLvjU

Any thoughts what is going on? Nothing has changed on my account and as I love using the Mail app I'd like to try and fix this. Currently I don't like the idea of doing some tasks on the web interface and some in the Mac Mail app.

Thanks,
Chris.