I just saw this post and thought it needed explaining.
Basically the DC5 has a built in safety feature which prevents reverse from being selected over 6mph. Over 6mph the full right hand position is up = 5th and down = 6th.
When your stationary or below 6mph the selector inst engaged and therefore furthest right hand position is up = nothing and down = reverse. < essentially the selector goes further to the right>
If you go marginally to the left of the furthest point to the right it will select the 5th and 6th gears no problem.