I give booking, that are almost all of the time within the hour I say I will come. If I cant come and can fit them in another day I will call and arrange it. But generally I will go out in bad weather.

If he keeps canceling he will loss all his customers. Also he might not be conpletely ligit, in the sense of licence, insurance, tax returns etc and is not really bothered or examining the business aspects of a poor booking system.
You'll be there years after him and doing contracts he would never get in a million years, just smile and say thanks as his customers drop him one by one and call you.
gerard
