I put myself in my custies shoes and thought, 'would I like my W/Cner to just turn up and get water all over the floor without telling me first?'
The answer was No! So I told all my custies ahead of time left some of them with a note explaining the change and the reasons why. There were a few that I didn't get to tell. I had a few problems with both. The worst reactions were from those I didn't tell, though they appear to have come round now.
I told one that I wouldn't accept payment until I was sure he was happy. Went back, no problems. Payed straight away.