You include ebay final value fee, pay pal fees, postal fees especially on something to new Zealand would have been 10%, i'm guessing for those two glasses packed would not have come under 1kg so £22.80 at least and uk tax on profit at 20% and the initial cost of the item, thats what i have to pay, have you not sold an item on eBay as a registered business seller ? it works out for every 10 quid made you loose nearly half depending on how much you paid for the item in the first place, i'm going on selling something for i have paid a pound for and selling it for ten.
If you sell regular on ebay for profit your classed as a business seller.
I should know i have submitted 5 tax returns so far, ebay is all traceable its not like cash in hand at a fair.