what if the areas you cover have 4 different "local" dialling codes, in my areas there are places quite close together but with different codes, so using an 0800 number gets rid of that problem, I cant remember how many people that have said, if I knew you were coming from 10/15 miles away then I would have phoned someone more local, (even if the local guy is a muppet?), I know people want to deal local, but how close IS local, I think anything within a 25 mile radius is pretty local, anyhow I use 0800 no's and they have served me well. so if they are going to be free for all to use then even better.
