Have a look here:
http://www4.cd-wow.com/detail_results_2.php?product_code=12973
16.99 quid for the Region 1 three-disc set - even with vouchers/URLs, that`s still more expensive than DVD Soon...
I have a feeling that you`ll only have to wait until the New Year and this will come down in price (witness the 3-disc Spider-man deluxe edition - now 9.99 quid at play.com at 9.97 quid [+P&P unless you spend 19 quid] at amazon.co.uk and it`s only been out for 4 months).