Thanks @Manderley @janeg @Sassy1 @Azureblue for your prompt replies.
I'm definitely at the Manderley & Janeg end of the spectrum. It is only noon here in the UK and I have already drank about 6 x 300ml glass of still water (context is that although this is a fast day, I also jogged for 30 minutes so need to re-hydrate as well)
This is a significant increase to normal as I am trying to get my body to let go of the water it is hoarding!
Reason is although I feel great on ADF I have gained 1.5 lbs in weight since yesterday so it is obvious that as I am running every other day and fasting every other day the only reasonable conclusion is that I am retaining water...
Hence I am drinking alot today and like @janeg running up and down the stair often

I hope that this continues over the next few days and shows on the scales.
Wibbles