i dont know if this is still relevant but i live in the uk and i get mine from play.com 10 for £9.99 Free P&P
dont bother with the 25 and 50 pack as it would be cheaper to buy them in 10s
http://www.play.com/PC/PCs/4-/7871837/Verbatim-43666-DVD-R-8x-Dual-Layer-Disc-10-spindle/Product.html
the disc id: MKM-003-00
Supported Write Speeds: 4x, 6x, 8x, 10x
they are made in Singapore