I don't know about the exact implementation of these new rules because all my stuff from Banggood is arriving from China with no problem, no duty or VAT paperwork. Admittedly the last thing I bought cost me £30 and the customs declaration said £3.18.
What would a 30 pound parcel bring -6 pounds of revenue? Probably safe on the small things for quite some time as the customs folks know where they make their money.
We do have things that require duties in the states, but they're usually archaic competition-related things (like a 9% increase on the price of japanese guitars, and on an individual basis - someone buying a guitar from japan - only over a fairly high value threshold)