@Sleeptillnoon thanks so much for your reply & especially the pictures! I obviously want to see the unit "in the flesh" but haven't found anywhere nearby.
Do you know if the worktop bit is solid or more moulded like a kitchen sink?
The cut end would be butted up against the soil stack, which is wider than the worktop depth.
I'd also be using different units, and would have a short 70mm length of filler between the base unit and the end of the run, so no lack of overhand issues etc.
I'd had a response from the manufacturer which said it couldn't be cut, but the bathroom supplier (who make the units) just said it wouldn't be a finished edge but as it's up against a wall it wouldn't matter.
Pic is the 3D rendered image, the soil stack will be built out to be wider than the worktops so it won't overhang like in the image.
Now have to decide whether to go with the bespoke pink units, or just the standard 3 x 300 cupboard run and use one of the doors for filler to reduce the size to the space.