Cracking cheese gromit

A UK client has began selling goods on Ebay. He buys them from China,when he receives them in the post no import duty or VAT is charged or even mentioned.

He sells them on Ebay and his turnover is £6k a month (soon he will reach the VAT registration threshold)

What is his position regarding Import Duty,VAT and Customs Duty. He has done nothing regarding this at present.

What should I advise?