The bumper is easily removed, and describe here is nothing special.
Front bumper
Unscrew the screws in the front part under the plugs and the wheel arches under the wings.
Rear bumper
Unscrew the screws holding the brackets to the spars and free holders in the wings.
How to remove front and rear bumper Ford Transit (2000-2006)
How to remove front and rear bumper Ford Transit (2006-2013)
How to remove front and rear bumper Ford Transit (2013)