Laaaame ebook pricing
As jai already says, a 20% VAT (although high) is no excuse for this cost. EBook publishing costs very little (I'm not going to say "it costs nothing" because there's still labor costs to make sure the EBook looks good and all that...) EBook publishers know this and typically kick back a much higher percentage of the cost to the publisher compared to paper publishing (which really is quite expensive, especially with high paper costs of late.)
I've read both sides of the coin...
Those who "get it", they'll have a $10 or $20 book, but the EBook is like $3-$5.. sometimes it's more, but usually not more than half the cost of the physical book. They make good money selling the EBook if the book is any good, they don't have to worry about remaindered books being shipped back from book stores, or getting into those stores to begin with, or distribution costs, and so on for those EBooks, it's esentially pure profit.
The others will be like $12 for the book, and like $11.50 for the EBook... sometimes they consider the EBook "premium" and charge MORE for it than the physical book! They don't sell many EBooks, and just think EBooks are a bad market, rather than realizing the market is great, they've just priced themselves right out of it.
You know which category I think Rowling is in here.