Wanted - Billy Reid peacoat in Navy, size medium.

I'm really keen to get the Billy Reid Peacoat however I would like to spend under £500, this doesn't seem like a big ask with lots of sales online and what not however the import tax and duty seems to bump it way up, does anyone have experience with the duty costs? I seem to get quoted by most online retailers £150 but i'm wondering if I opted to pay it on arrival would it be as much as that, £150 seems excessive?

Or does anyone know of any good sales or anything in the UK or anyone selling one?

Any help appreciated.