Yeah, you will most likely get charged VAT & Duty on this. If you calculated it as 25% of the total item + delivery cost it's normally about right. The delivery company in the Uk will also charge a handling fee, parcel force charge around £8 and won't release the item(s) until charges are paid. Customs tend to hold the item(s) for around a week, whilst they calculate charges so you will need to take this into account.
I think now even if you send something as a gift and it's over a certain amount they will also charge you for this too. Have a look at the HM Revenue & Customs site on importing.