Soundboard fixing; shove coupler

The soundboard has been fixed in position, with clamps on the belly rail, and nails with ply 'washers' along the hitch-in rail. The washers avoid possible damage when removing the nails. There is also a brief clip of the shove coupler moving in and out. This has the effect of linking the upper manual to the lower, so that both 8' choirs can be played together