Dishwasher panels are a standard size so 715 x 597 (although some can be 595 wide). When you say soffit what do you mean? If it’s an integrated dishwasher which I presume it is you don’t need an end panel or carcase as the door fits directly onto it. Can you just remove the end panel or will that make the gap too big?

Also be aware that some integrated dishwashers need the plinth to be cut to allow for the swing down of the door.

Thank you for replying Daisy. That’s a good idea. Maybe we could remove the end panel or move it over to the other side next to the cabinet as a filler? I know that’s not ideal but I think better than where it currently is or leaving a gap? It is a built in dishwasher and the toe kick will go across the bottom of the cabinets and dishwasher after the dishwasher is in and we can check the measurements.

Oh and the soffit is on top of the upper cabinets. There is a pipe that can’t be removed so we had to hide it.

Is it permanent or was it just to help the worktop templates?

Good question. When we looked underneath it looks like the plywood and some metal bars might be bolted into it but I am trying to find out. Contractor has not replied today but I will come back with his answer when I get it. Another idea my friend had was to add a piece of the quartz to cover it and try to match the design as much as possible but not sure if that will look worse.