Shipping costs to UK

Hi there,
I ordered the new Umbrel Home in February and it was received 27 Feb.
The cost on the Umbrel website was £319 including shipping.
Today 17 Mar, I’ve received a FedEx invoice requesting Duty & Taxes of £49.05 !!
Looking at the FedEx paperwork the value of the Umbrel Home was 239 US dollars (about £191).
The math doesn’t add up.
Did I overpay?
Surely Duty & Tax is part of the shipping costs.
Can anyone make sense of these numwers please?
Thanks
Stan