I found the following information somewhere around the time the charge for using certain diesel cars within the area affected was introduced.
As you know by now that using an old diesel car you have to pay a charge to enter certain areas. The areas will be extended to surrounding residential areas. As a disabled vehicle you will not be exempt. You will need to pay a reduced charge. I will see if I can find the info.
As one of the poster says it applies to older diesels. Those using motability cars will have diesels that meet newer emissions therefore should not be affected – for the time being.