Northdown Hops, anywhere?

I'd like to brew the recipe for Sam Smith's India Ale out of the BYO Clone recipes issue. This is one of my favorite beers and I'd really like to follow the recipe as exactly as possible. I can only find them for sale by the pound at NorthernBrewer.com but they are missing some of the other ingredients I need. The only other places I've found them are across the pond.

I've read that there is really no good substitute for this variety. Anyone seen them available anywhere recently?

I also came up short, found a place in Australia and the UK. I did read a lot that Northern Brewer is a good hop substitute for it though.

The Northern Brewer Homebrew Forum • View topic - Northdown Hops -- where to find

I'm interested in the recipe, as I've got a Northdown plant.