Whilst you are talking about costs for shipping, please let me just explain why the costs may be quite high:
On the occasions I have shipped long distance from Europe (Germany) I have always preferred to use "Air freight". This ensures the parcel is insured (up to a value of €500) and gets it to the destination reasonably quickly. I am also told by the Post Office that "Air" parcels are handled more carefully than "Land" ones.
The minimum for an "Air" parcel is 5kg weight, which depending upon bottle style and size, could mean either 2 or 3 bottles.
However, the basic cost of this to say the USA, is €48 (32 GBP).
If a seller includes just €2 to cover packaging, then it is quite feasible to have a P&P cost of around €50 (almost 35 GBP). However, as I said, this will certainly cover 2 bottles, sometimes 3.
If a buyer really isn't worried about delivery times or insurance, then "Land" would be at a cost of €32 for the 5kg.
There is one further option, that of "small packet" rather than parcel. But this has a maximum limit of 2kg in weight which can be quite difficult to achieve with some heavier bottles (like the heavy Bruichladdich ones), but this would only cost €12.90 by land, €25.80 by air.
As for Australia & Japan:
5kg Air & Insured - €58
"Land" - €37
So as you see, the high prices are not necessarily sellers being unfair, but the actual cost of postage.