Miele dishwasher leaks (F70 error) only when the drip tray is attached

Help. I’ve replaced 2 x door seals and the circulation pump seal on my Miele Futura Classic G4286SCVi dishwasher. The circ pump seal had a hole in it and needed replacement.

I run the dishwasher on blocks with the drip pan off and there are no leaks whatsoever.

When I reassemble and install the dishwasher the F70 error eventually comes up signalling the drip pan is full of water and the float is activating the microswitch.

It seems the drip pan is putting pressure on a part that then leaks when it is in place?

Any help is greatly appreciated. I may try fixing the dishwasher with my axe soon.

Thanks