Those "centers" are background-image positioning. They have nothing to do with the centering of HTML elements on your page, so you can set those back to what they were.
What donboe is talking about is this, in your HTML (not your CSS):
<table width="95%" border="0" cellspacing="0" cellpadding="1" align="center" class="poll">
<td style="font-weight: bold;">
What requires most improvement in Wellingborough? </td>
If you put an ugly background colour on that td, and then different background colours on the inner td's inside, you'll see that while the inner td's are aligned left (the radio buttons inside are as left as they can be), they themselves are forced to center because you have the align=center on that td I highlighted above.
So, you should get everyone moved over to the left if you just remove the align="center" there. You shouldn't have to say "left" as that's the default.