When doing your usual ‘BLACK’ routine when hitching on a trailer, always remember and check when you put the handbrake off that the ‘shunt’ button is out as well.
Put a trailer on the back the other day, pulled away fine, then about 2 miles down the road i had to stop at a set of temporary traffic lights. Hand brake on, waited, lights changed to grenn, hand brake off, tried to pull away, nothing, wouldn’t move. First thing i thought of was some ■■■■ had stuck the handbrake on when walking passed. Got out had a look, handbrake was fine. Tried fitting refitting suzys and all was ok that end, also air pressure was at max. Had a look at handbrake again just to double check and noticed the handbrake and shunt buttons were both in. Seems the shunt button was really stiff and hadn’t popped out when the air line went on.
I will be checking that from everytime now on 
)
PMSL