Hi Trevor
I am doing this holiday on the 12th September and looked back on several threads and the general consensus seemed to be around £150.00 worth of Remimbi. My bank issued me with 100 Yuan notes, this is the highest denomination, so I hope that I don't have a lot of problems changing them, when I only have a small purchase. The other advice was to take £10 and £20 notes that are newish and not written on. Change these at the hotels as you get a better rate. Use your cards for any large purchase.
Hope this helps and that the floods have receced.
Peter