The customs charge will be just VAT but will be based on the seller’s statement of value on the package. We have encountered inflated charges caused by inflated statements of value which result from the seller seeking scam their mail insurance. If they value we an item at £100 and it goes missing in transit, they are quids in. Your only option is to challenge the HMRC charge using proof of what you paid for the item, which is below the threshold for charging VAT on imports by post.
Thanks Giuliano, done a little light reading and it appears to work like this
I’m guessing in my case the sender has over valued the goods for a possible insurance scam.
I’ll be contacting the seller for a full refund. Out of principal rather than loss. As my Mother, God bless her, used to say ‘look after the pennies and …’