Was that the dearer 2.2Kw one ? Without having previous dealt with whoever you don't know how they list the customs returns.
So far no one has ever listed the contents correctly as regards price.

I have noticed thought that whilst goods from China seem to get passed over, goods from the USA get hammered every time.
Even had repaired boards charged for again when sent back, try arguing that, you can never find anyone interested and Parcel Force state on their form they will not get involved.