One other thing that I needed to do on the frame was to cut and fix four upstanding boards on which the lower mahogany panels will sit. This being done it also afforded an opportunity to check that my measurements were OK and that I had left enough room for the retracting keyboard to pass between the two side panels and below the two small stop jambs. So I clamped the panels onto the front of the frame where they will go as shown here and measured the relevant gaps
I know from past experience that it pays to check things like this as you go along. The earlier you spot a mistake the easier it is to fix! One way for errors to creep in is that I am drawing the plans at 1:2 scale and it is the easiest thing in the world is to take a measurement from the plans using a ordinary ruler rather than the scale ruler.