Warning to parents as illegal car seats are being sold onlineThe car seats have been found selling on eBay. (Image: Which?/PA Wire)Buckinghamshire and Surrey Trading Standards have previously dubbed the products “killer car seats”. Child car seats must have an R44 or R129 regulation label to be sold legally in the UK. head of consumer protection policy, said: “It is appalling that these deadly car seats are reappearing on online marketplaces more than a decade after Which? They were a harness type system intended to replace a child car seat to save space.