add the following code just before the closing </form> tag:
<input name="select_colour" id="select_colour" type="hidden" value="<?php echo((isset($_POST["select_colour"]))?$_POST["select_colour"]:"") ?>" />
<input name="select_style" id="select_style" type="hidden" value="<?php echo((isset($_POST["select_style"]))?$_POST["select_style"]:"") ?>" />
<input name="select_printoption" id="select_printoption" type="hidden" value="<?php echo((isset($_POST["select_printoption"]))?$_POST["select_printoption"]:"") ?>" />