FB Messenger on wesite help

Hey folks. I am using the Facebook chat on a website so people can chat with the business owner without having to leave his site. On the laptop and PC it looks perfect but when I go to the site on my mobile (or any mobile for that matter) the logo for chat is slightly off screen and the page can be moved left to reveal it. I all have to zoom out (using the two finger pinch on screen) and then it looks awful. Is there anyone who can help as to why this has happened. A link to the site in question is www.bgdrivingschool.co.uk If people can check it out on both pc/laptop then on mobile device you will see what I mean.

Many thanks in advance folks.

Asked about 2 months ago