This is great stuff!....and I concur with andy, you are "the man" DAAB!
DAAB, one point concerning your comments on water. For one of my brews that had this bad off flavour, I used ASDA bottled spring water?? Although I must stress that this was my first brew using steeped grains (black patent), and a lot of these grains "escaped" from the grain bag and ended up in the boil, so the bad taste may have been tannins? (it was the worst of all of them, really strong off flavour).
Anyroad, I think I shall have to get one of those filters.