Manual here:
http://samproperties.co.uk/tenant/wp-content/uploads/2011/04/Tricity-Bendix-AW850.pdf
Form the manual:
The drain hose may be squashed or kinked.
The “rinse hold” or “no spin” option has been selected.
The drain pump may be blocked.
The drain hose extension, if fitted, is not correct. Follow the instructions for connecting to the waste.
The drainage system pipes are blocked.
The wash load is unbalanced: redistribute the clothes inside the drum to allow the machine to spin.
See pages 17-20 of manual
X, February 2015