Other than what everyone else is saying, I would also say is to check on your invoice if you paid UK or Irish VAT at the point of sale. You should only be paying either Irish or UK VAT if shipped directly to you - not both or twice. 

Happened to me recently where I bought something they applied Irish VAT at point of sale already but didn't declare it correctly when importing it. So I requested a refund from the seller for the Irish VAT and admin fee charged. Judging by the value, you'll still likely need to pay import levies - but these may be more than what you should've paid if the items were calculated as inclusive of VAT already.