The duty is calculated on the CIF UK price ie - the supplier's invoice value plus any sea freight plus any insurance paid. Add these all up and multiply by the duty percentage.
The vat is calculated on the Delivered UK price is - the supplier's invoice value plus any sea freight plus any insurance plus the duty amount plus the UK charges. Add these all up and multiply by 20%. Please note, Customs accept a figure of £550.00 per container to cover the UK charges . It is not the true UK charges but just a figure that they accept for calculation purposes.
8418290000 Other - 2.2%
Vat is 20%