introduce yourself,shake his hand,give him a business card and tell him your price,frequency and that you can clean his conny roof/fascias annually for him if he wants.
a quick explanation of your payments methods(cash on the day,cheque or BACS)
tell him you clean all frames,doors and sills as standard and that you work in light/medium showers and all year round.
note his phone number down as well as his address.job done!
if he wont accept the above then dont even take him on!
no need to make it more complicated than it needs to be!!