Have you set table style="table-layout:fixed" ? Also, please let me know the sample structure page and the step by step to replicate the issue. I think the grids are aligned well. Only the position is not fit well inside table. Maybe some of the style needs to be customized first.

Regards,
Handy 

The table structure can be seen below. It is always the second grid which has the issue but this only happens sporadically.

 <table>
            <tr>
                <td class="PanelHeading" width="455"><%=SetCustomStringValue("Clerk Takings")%></td>
                <td <%= (IsNotToday ? "style=\"display: none;\"" : "") %>> </td>
                <td <%= (IsNotToday ? "style=\"display: none;\"" : "") %> class="PanelHeading" width="455"><%=SetCustomStringValue("Terminals")%></td>
            </tr>
            <tr>
                <td>                        
                    <table cellpadding="0" cellspacing="0" border="0" style="table-layout: fixed;">
                        <tr><td>
                            <ISWebGrid:WebGrid ID="wgTakingsClerk" runat="server" Height="180px" Width="450px" DataSourceID="sdsTakingsClerk" />
                        </td></tr>
                    </table>
                </td>
                <td <%= (IsNotToday ? "style=\"display: none;\"" : "") %>></td>
                <td <%= (IsNotToday ? "style=\"display: none;\"" : "") %>>
                    <table cellpadding="0" cellspacing="0" border="0" style="table-layout: fixed;">
                        <tr><td>
                            <ISWebGrid:WebGrid ID="wgTerminals" runat="server" Height="180px" Width="450px" DataSourceID="sdsTerminals" />
                        </td></tr>
                    </table>
                </td>
            </tr>
        </table>

Ok, have your tried my suggestion? I saw that you haven't put the style I suggested. Actually, i need the whole structure page, not only the table.

Regards,
Handy