On receipt of your order we will visit you, initially to survey the glass. This will include determining the type, overall thickness, cavity between the glass and of course the precise height and width measurements.  
If there are lead panes or a Georgian style pattern we will also record these details. Installation is approximately two weeks later but we will telephone you to arrange a convenient day and time.

Each unit is changed in less time than it takes to make a strong cup of tea. No mess and no disruption.

That's it - Done.