If you have Internet signal issues, tell them that is the reason you can't have one fitted.
In my case, EDF had visited & their engineer told me that I had no internet signal due to where my meter was. So when I still got calls to have smart meter fitted, I told EDF what their engineer said, and the hassle calls stopped as they put a note on my account.
In Scotland, and can only assume the same in England, there is no legal obligation to have a smart meter. When they were first introduced, people were led to believe that there was no choice in the matter, but when folk I know found this out, they wanted them removed. Only to be told by their energy suppliers that it would cost £80 to have the meters removed!
I know that if your current electric meter is on it's last legs, the new one fitted will be for a smart meter. Also, currently a lot of energy deals only apply if smart meter fitted. I did mange to get a deal when I told them about Internet issue. If you don't ask, you don't get is how I look at it.