Displaying a blue badge may or may not get you free parking at a station car park. It depends on the TOC and who runs the car park at the stations. I cannot comment on the parking at Midlands stations but at most large stations on the south coast, blue badge holders have to pay the going rate but can of course park in one of the disabled bays, provided that the blue badge is displayed. Some smaller stations which do have a small car park may not impose parking charges on anyone.
Make sure that you read and understand the booklet that came with the blue badge. Free car parking is generally only available at Council run sites, some will let you park for free in any bay whilst others charge you if you park in a non disabled bay even if you display a blue badge.
Don't assume anything but check the notices regarding disabled/blue badge parking at any car park you are in
