Thanks MJ.
The genuine Audi brand new one I have (4D0959931) came from the US, the supplier still has some and they're about US$80 each. Can't recall what I paid back when I got mine but the final price with shipping and import duty works out now to just over £100 to a UK address.
The part number is 8360408. Don't use the Audi one its an inferior design and has the same fault as my valve block had