Have been back from Cawood just over a week I thought I would try the Floe again,this time with all the taps shut.
As I surmised previously I got out just over 200mls, plus what came out of the hot water tank.
What came out was a dirty brown colour.
In my humble opinion I think this proves the worth of the Floe and its admittedly high price for what it is ( round about £40 ).
200mls is enough to freeze during the winter with the resulting damage of pipework etc.,although admittedly I had no problems last winter pre-Floe.