Bosch SD13GT1B not draining

Hi,

All of a sudden my slim-line dishwasher has stopped draining. I can’t find the manual or download it. I’ve searched this forum for suggestions but this model isn’t mentioned. I’m stuck trying to access the pump cover so I can check for blockages and the state of the non-return valve. There’s a grey plastic cover under the lower arm secured by 4 torx screws but it won’t come off – the salt holder and the pipe feeding the upper arm stops it and I don’t want to force it…. And I’ve got no idea if you need to access it from the bottom of the machine or how to do it if you do!. Can anyone give me any pointers? With Christmas fast approaching this is the last thing I need!

Many thanks

Irvin