Editing Linq results in a GridView

Question

I have the following Linq Query which links data from SQL Server and an ODBC source (Cache as it happens)

            Dim items = _
            From p In dtCurrentPatients.AsEnumerable() _
            Group Join s In dtScores.AsEnumerable() _
            On p.Field(Of String)("HospitalNumber") Equals s.Field(Of String)("HospitalNumber") _
                Into PList = Group _
                From HasScore In PList.DefaultIfEmpty() _
                Select New Patient() With { _
                    .Score = If(HasScore Is Nothing, String.Empty, HasScore.Field(Of String)("Score")), _
                    .LastScored = If(HasScore Is Nothing, String.Empty, (HasScore.Field(Of Date)("DateTimeScored")).ToString("dd MMM yyyy hh:mm")), _
                    .HospitalNumber = p.Field(Of String)("HospitalNumber"), _
                    .Name = String.Format("{0}, {1}", p.Field(Of String)("Surname"), p.Field(Of String)("Firstname")), _
                    .Bed = If(HasScore Is Nothing, String.Empty, HasScore.Field(Of String)("BedNumber")), _
                    .HandOver = If(HasScore Is Nothing, String.Empty, HasScore.Field(Of String)("DiagnosisPlan")) _
                    }

This is then used in the following Grid

<asp:GridView ID="grdDependency" runat="server" CellPadding="4" ForeColor="#333333"
                GridLines="None" AutoGenerateColumns="False" 
                BorderColor="DodgerBlue" BorderStyle="Ridge" BorderWidth="4px" EditRowStyle-ForeColor="Bisque"
                Font-Names="Arial" Font-Size="8pt" Width="90%" AllowSorting="True">
                <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                <RowStyle BackColor="#EFF3FB" />
                <EditRowStyle BackColor="#2461BF" ForeColor="White" />
                <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
                <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                <HeaderStyle BackColor="#507CD1" Font-Bold="False" ForeColor="White" Font-Names="Arial"
                    Font-Size="8pt" HorizontalAlign="Left" />
                <AlternatingRowStyle BackColor="White" />
                <Columns>
                    <asp:CommandField ShowEditButton="True" HeaderImageUrl="~/images/edit.gif" />
                    <asp:TemplateField HeaderText="Hospital Number">
                        <ControlStyle Width="35px" />
                        <ItemStyle HorizontalAlign="Left" Width="100px" />
                        <ItemTemplate>
                            <asp:Label ID="Label2" runat="server" Text='<%# Container.DataItem.HospitalNumber %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>                 
                    <asp:TemplateField HeaderText="Patient">

                        <EditItemTemplate>
                            <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
                        </EditItemTemplate>
                        <ItemStyle Font-Bold="true" />
                        <ItemTemplate>
                            <asp:Label ID="Label1" runat="server" Text='<%# Container.DataItem.Name %>'></asp:Label>
                        </ItemTemplate>
                        <HeaderStyle HorizontalAlign="Left" />
                        <ItemStyle HorizontalAlign="Left" />
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Dependency Score">
                        <EditItemTemplate>
                            <asp:DropDownList ID="DropDownList1" runat="server" Text='<%# Container.DataItem.Score %>'>
                                <asp:ListItem Text="0"></asp:ListItem>
                                <asp:ListItem Text="1a"></asp:ListItem>
                                <asp:ListItem Text="1b"></asp:ListItem>
                                <asp:ListItem Text="2"></asp:ListItem>
                                <asp:ListItem Text="3"></asp:ListItem>
                            </asp:DropDownList>
                        </EditItemTemplate>                        
                        <ItemTemplate>
                            <asp:Label ID="Label3" runat="server" Text="<%# Container.DataItem.Score %>"></asp:Label>
                        </ItemTemplate>
                        <HeaderStyle HorizontalAlign="Left" />
                        <ItemStyle HorizontalAlign="Left" />
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Last Scored"> 
                        <ItemTemplate>
                            <asp:Label ForeColor='<%# GetLastScoredColour(Container.DataItem.LastScored) %>' ID="Label4" runat="server" Text="<%# Container.DataItem.LastScored %>"></asp:Label>
                        </ItemTemplate>
                        <HeaderStyle HorizontalAlign="Left" />
                        <ItemStyle HorizontalAlign="Left" />
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Bed">
                        <EditItemTemplate>
                            <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label5" runat="server"></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField>
                        <EditItemTemplate>
                            <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label6" runat="server"></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
            </asp:GridView>

However when I click on the EDIT Command it still does not allow me to actually change values in the grid.

What really obvious thing am I missing?