I should mention that Noby had trouble with head retention, in some of his beers, after switching to this solution, but I did not.
My latest bottled beer (the Weiss I brought to the tasting session last Thursday) did have head retention issues though and I have my suspicions.
I switched to Tesco plain white bleach, where I had been using Milton, with no trouble. I am going to switch back and see if the problem goes away.
Séan