Bosch wff 2001 not emptying water!?

My Bosch wff 2001 is not emptying water. The wash cycle proceeds O.K. 'till the time to empty the wash water, then the water is not emptied and the cycle eventually stops. If I drain the water manually from the drum, using the drain hose, then the cycle will proceed normally.
I thought that something might be blocked/caught in the filter, it may be a shirt collar stiffener, but this is not the case, so far nothing has turned up in the filter.
How can I access the insides of the washing machine, from the top, bottom or rear?

Thanks for any help