Thanks for that tsc, not sure if Steve comes on here very often but can't hurt to flag it up.
Your walk sounds great, Yatesbury is a bit out of the way from Broad Hinton but am certain the fields around the Winterbourne must have been flooded. I did a 'bus' walk about a month ago with my local Ramblers group - the leader took us via Broadtown and Cliffe Pypard. We encountered mud, mud and more mud - not to mention a dead sheep and electric fences across footpaths. Started just after 10.30am and limped into Avebury at 4.00pm having waded through water ankle deep to get across the last but one stile. Avebury never looked more peaceful and welcoming (just to finish the afternoon off nicely I almost got locked in the toilets). It was a wonderful walk overall though.