All depends if customs picks it up which is dependant in the declared value and how it’s posted (eg Royal Mail or DHL).
My DX3Pro sailed through and no fee but my £20 cable from aliexpress was picked up and charged.
Believe it’s just 20% vat under £135 then another 3.5% duty if over £135. Under £15 items are vat and duty free.
Royal Mail also add in £8 handling fee
All depends if they pick up the item or not.
I was going to try one but will get the March Audio DAC if I need to replace my DX3Pro.