How can I completely disable child lock on Bosch Exxcel dishwasher?

The model is SGS 57 E22GB/75. Whenever the door handle is pulled a yellow lever pops out. It can be pushed back in with some fiddling and I have tried to disable it following the pictures in the instruction booklet but no luck! Does anyone know how to fix this? We are having to pull the door open from the side because it's quicker than messing about with the child lock.