To continue further

The outer wing panels as supplied ans also the tailplane have pre -milled circular holes which I assume are to accept a particular type of servo mounting box.(photo 1)

As I don't have any I have made up boxes from balsa / spruce for the servo mounts, the gaps to the sides will be infilled with expanding foam and the whole sanded smooth. You also need to let in a 6mm x25mm x50mm ply plate centred on the wing tube to accept the wing retaining screw which will be drilled and tapped into the wing tube (aluminium).(photo 2)

Other work today was installing the steering servo mount.