It works now just by using:
<asp:Label ID="Label1" runat="server" Text='<%# Eval("BranchGMT", LocalTime(Container.DataItem("BranchGMT"))) %>'></asp:Label>
instead of
<asp:Label ID="Label1" runat="server" Text='<%# Eval("BranchGMT", LocalTime("BranchGMT")) %>'></asp:Label>
:D
Mental block is now cleared, I'm just waiting for the hair to grow back now!