Two things here.
"He was polite and apologetic but said the firm wont allow inspection as they would never get round all customers." I suspect this stemmed from the driver, not the firm.
Everything is so well packed these days. Just minor scuffs or a dog-eared corner can safely be ignored but if the box has clearly been opened or has a wound that looks like it was attacked with a hefty spike that would be grounds to reject the parcel.
Perhaps a mid-way out with severe damage, might be to accept the hurried delivery and be on the phone to Dell for guidance.