Okay so after playing around with this I found that the problem was the background image with the up and down arrows. There is a line in the image. I used the CSS to move the image to the left instead of the right and the numbers don't land on top of it. I also added some padding to move the numbers away from the up and down images.

Here is the code I used:

#wpforo #wpforo-wrap .wpf-navi select.wpf-navi-dropdown {
padding: 1px 20px !important;
line-height: 20px;
}
#top .entry-content-wrapper select {
background-position: center left;
}

See attached image, I am happy with this now. Could look better without so much white space, but due to the background image, I had to leave a lot of padding to make it look centered.

Now understanding this, I am guessing you are not showing the background image on your forum and turned this off in the CSS.