Can you specify in the order to contact you if a fault is detected, before proceeding with the remainder of the order? Or to simply cancel the entire order if there is a problem with any of the boards?
" . . . reviewer for distances & clearances . . . "That's what running DRC (Design Rule Checking ) does.
I know, I have been using DRC (on Eagle) for years as well and it does miss things sometimes.
KiCad user myself but that's not simply because you didn't set up the DRC rules according to the specs of the fab house? Default DRC rules are pretty generic but they may not be correct for every fab house.