Well, Diane slipped out to see a neighbour so I've been able to take a set of photos showing the assembly involved in the sides, the lift-up shutters, a fold-down step and, for the right-hand side, the RC aerial. As the RC aerial is the only difference between the two sides, I've concentrated on the right-hand side only.
The first photo shows the parts involved. The shutters are two different widths, the front and rear ones being narrower than the centre one, something often found on fire egines. The RC aerial is in two sections, a narrow tube and a detachable tip. Presumably as the tube is just that, a tube, the receiver element is in the tip.
The shutters fit on easily if you offer them up in the closed position and then just push them firmly home. They open and close with a satisfying click so there's no risk of them flying open as the vehicle corners and equipment flying out (it happens!). The step, the red piece in the first picture, fits at the bottom of the forward locker. This is a common feature on German fire engines and is also appearing more in the UK.
The shutters click into a locked position before reaching the vertical, although they can be pushed up to be vertical. However, they look much better open at an angle. The step folds down to allow access to the lowest slide out equipment tray and to make the higher equipment trays more accessible.