Not many but I have refused about a dozen new enquiries because of various problems that put me off. I am now getting very choosy about what I take on. I won't do old windows and access is a big problem round here which ever way you work.
On the other hand, I will now take on leaded which I wouldn't before and there are thousands of houses with leaded glass that are potential new customers for me. Also a large number of the new enquiries from my recent leafleting campaign are leaded windows . This leads me to believe they always has trouble getting a WC in the past.
In reality there are not many houses that are unsuitable for WFP that wouldn't have been just as unsuitable for trad.
In general WFP is more flexible and the question is not how many customers have you had to drop its how many more customer you are able to do