“50 cm” shouldn’t be a problem.
I wonder if it has anything to do with the credits. I just tried uploading your sink file to the 3D Warehouse and had a message it could not verify ownership. Checking credits I see the following.
I’m thinking that the Warehouse is comparing those credits with my account and sees that I’m not the one who authored the model or some of the components within.
By the way, who is the target audience for this model? The manufacturer of the sink?